Sunday 14 February 2016

MegaList

*********************************
Topics covered here:
DS & Algo
Java
Multithreading
Collections
Spring
Hibernate
Design Patterns
SQL
Web Services
OS
Networking
Puzzles
HR
Other General
*************************
Combined problems
IPC
Beautify input json
Given string and regex , give no. of times it occurs.
Find next greater number with same set of digits
Determine whether a point is inside a polygon?
Number of squares in chess , gneralize it
Tug of War problem
Given binary tree , sum of each level
Length of longest substring with no duplicat character
8 ball puzzle
Design parking lot
paging in os
regex for email
Given BST , traverse only left sub tree
Red Black Tree
AVL tree
Find the maximum number that can be formed from the digits of given number
Design elevator ,
parse xml , store outpout in json
find prime number in given range
what are cookies
how to maintain sesion
angle between hour clock and minute
Design data structure that supports insert,delete , find max , delete max in O(1)
Convert roman to integers and vice versa
Number of BST from 1 to n
Given array , create another array which contains product of all elemetns except ith aray , witout using divioson.
Implement hash tables
find maximum weight matching in bipaartite graph
3 , 7 , 5 liter milk container puzzle
sort stack using only another stack
how threading works at cpu level
thrasing?
page replacement policies?
paging?
page fault?
How a server works?
compilation vs interpretation?





Questions-to-Ask-Hiring-an-Offshore-Call-Center-Services-Provider
DS , Algo ,Bit Magic (Solve each problem in every possible way)
1. Write code to find loop in linkedlist
2. Write code to reverse a linkedlist
3. Write code to reverse a string without using any API.
4. Implement Djikstra.
5. Write code for  DFS,BFS,inorder,preorder,postorder,zigzag in tree.
6. Implement quick sort.
7. Implement merge sort.
8. Implement autosuggest feature from a list of words.
9. Implement LRU.
10. Write code to find diameter, height of tree(or binary tree?).
13. Write code to check if a number is power of 2.
14. Write code to search a number in rotated array.
21. Write code to check if a number is prime.
Find LCA(Lowest Common Ancestor) in a binary tree.
12. Write code to find number of set bits in an integer.
5. Write code to find kth element from end in a linked list ?
6. Write code to find the missing number in an integer array having 1 to 100 in random order except a number.
10. Write code to check if linkedlist is palindrome.
12. Implement Prim.
15. Write code to search a number in a sorted 2d matrix.
16. Write code to print 2d matrix in spiral order.
17. Write code to find kth largest element in an array.
18. Implement stack using queue.
19. Implement queue using stack.
20. Implement two stack using an array.
21. Implement three stacks using an array.
19. Write code to check integer is palindrome.
19. Write code to check string is palindrome.
20. Write code to find maximum continous subarray in an array.
21. Write code to find longest palindrome substring in a string.
22. Write code to find best time to buy sell stock.
22. Write code to swap two numbers.
23. Write code to find sum of digits
24. Write code to reverse an integer.
24. Write code to print first n numbers infibonacci series.
25. Write code to print nth fibonacci number.
25. Write code to add two numbers represented by a linked list.
26. Write code for bubble sort.
27. Implement radix sort.
28. Implement counting sort.
29. Implement insertion sort.
30. Implement selection sort.
31. Implement heap sort.
32. Implement bucket sort.
33. Write code to find first repeated character in a string.
34. Write code to find first unique character in a string.
How to find middle element of linkedlist in one pass?
Write code to remove duplicates from an array.
Implement BST.
Implement doubly linked list.
Implement doubly linked list using single pointer.
Write code to convert decimal to binary.
Write code to sort a map by value.
Write code to find common elements in two arrays.
Find longest substring without repeating characters.
Determine whether a point lies inside a triangle.
Nuts and bolts problem.
What is the probability that knight stays inside the chess board?
Implement stack using likedlist.
Implement queue using linkedlist.
Check for balanced paranthesis in an expression.
Sort an array containing only 0 and 1.
Sort a linkedlist containing 0,1,2.
Minimum number of platforms required at railway station.
convert word to another , one time one character , from a list of words.
Break string into dictionary words.
Find seed of a number. A number X is seed of Y if multiplying X by it's digits equates to Y.
Finds pairs of numbers with difference k  from an unsorted array.
Find number of trailing zeros in a number factorial.
Given an array containing 0 and 1 , find the largest subarray cotaining equal number of 0 and 1.
Sort an array of elements by decreasing order of frequency.
Given an array of words , group all anagrams in set
Find the min element in a sorted rotated array.
Delete all leaves from a binary tree.
Find two elements in an array whose sum is closest to zero.
Given two rectangles if they overlap or not (Imp)Find max sub square submatrix in a 2d matrix of 0 and 1 with all 1.
Minimum coin problem
Rotate an array by k
Find the level of a given node in a binary tree
Implement heap sort
Implement priority queue.
Find difference in the sum of nodes at odd level and nodes at even level of  a binary tree.
Check for children sum property of a binary tree.
Inorder predecessor in a binary tree
Inorder successor in a binary tree.
Rotate linked list by k nodes
Sort an array of 0,1,2.
Find pair of elements in an array whose sum is equal to given number.
Check whether two strings are anagram.
Given a  linked list , each node has two pointers , one point to next , another to some random node , How to copy it  ?
Get intersection point of two linked lists. (imp)
count nodes in a tree
determine if two binary trees are identical?
Implement binary search algorithm(imp)
sort an almost sorted array with two elements swapped
merge two sorted array without using extra space , assuming first array has enough space
Find minimum distance between two elements in an array
Print all the leaders in an array.
Given a 2d matrix m of 0 and 1 , if m[i][j] is 1 , fill row i and col j with 1
Replac each element of an array with next greatest element.
Find row with max 1 in sorted matrix
Find the number occuring odd number of times in an array , rest occur even number of times.
Given k sorted arrays of size n , merge them.
Find all pythogorean triplets in an array.
Convert sorted array to balanced BST.
Find LIS contigous.
Find LIS non contigous.
Find sub array whose sum equals given number.
Find max diff. between two elements in an array such that larger appears after smaller.
Find majority(occurs more than half) element in an array in O(n).
Even numbers at even pos , odd at odd in an array
Find union and intersection of two arrays.
Find smallest positive number missing from an array.
Shift zeros to end of array
Reverse linkedlist in group of k
Remove spaces from a sentence.
Reverse each word of a sentence
multiply two numbers using min. number of additions
detect cycle in graph
print bottom view of binary tree
print top view of binary treeadd two integers without using +
randomized quick sort
In a 2d matrix , a sub square matrix is painted , find minimal/optimal cost of painting the rest using a fixed block. which block to use ?
Floyd WarshallA 2d matrix containing 0,1,2 , 0 -> empty orange , 1-> fresh orange , 2-> rotten orange , how much time so that all are rotten , a rotten orane will rot adjacent (not diagonal) in one time frame.
Given a binary tree, n and k , find sum of all nodes which are k nodes away from node n.
mirror a binary tree
check if two binary trees are mirror
Convert BST to DLL.
check binary tree is bst
convert sentence like 'these are twelve pens and two shirts. convert it to 'these are 12 pens and 2 shirts'. Inline
Given linkedlist of moves of 2 players on tic tac toe , find who won
Given pile of 9 objects , Pick 1,2,or 3. 2 Players , last one to pick is looser. Give winning strategy.
Given stream of integers , give me median at any time.
Construct BST from pre and inorder
Rod cutting problem
Deletion in bst
Implement using BST
How many bits need to change to convert one num to other?
Check MSB is 0/1 ?
T9 dictionary implement



Java
1. What is OOPS ?
2. How hashmap works in Java ? Difference between hashmap and hashtable ? What will happen if I put a key which already exists in hashmap ?
3. What is an interface ? Difference between interface and abstract class ? When to use which ?
4. Overloading vs overriding ?
5. Why string is immutable ?
6. What is difference between arraylist and linkedlist ?
7. What is difference between JDK, JRE and JVM ?
8. Why use getters and setters ?
9. Does Java support multiple inheritance ? Why or why not ?
10. What are the types of Exceptions ? How are they different ? What are the best practices for exceptions ?
11. Can we override private , static methods ?
12. What is generics , why use generics ?
13. Why can't we use polymorphism in generics ?
14. What is a thread ? What is a process ? What's the difference ?
15.  What is final keyword ? How it's used in java ?
16. What's the importance of serializableversionid ?
17. What if I put return in try block , catch block and finally block ? In which scenario finally is not executed ?
18. What is garbage collection ? How it's done ?
19. What is the use volatile , transient keywords ?
20. What is java memory model ?
21. String vs StringBuffer vs StringBuilder
22. What is thread safety ? What is race condition? What is deadlock ? What are the conditions for deadlock ? Give an example of deadlock. How to prevent deadlock ? What is livelock? Example?
23. Semaphore vs mutex vs lock vs synchronized
24. What is classloader ? Types? How classloader works ?
25. What is JVM? How does it works?
26. Can I overload main method?
27. What is ThreadLocal class? Why use it?
28. Wait vs sleep vs yield?
29. Is java compiled language or interpreted language?
30. Executor.submit vs Executor.execute?
*****************
Is java platform independent ? How ?
static class vs singleton
thread lifecycle
.throw vs throws?
Error vs exception?
What are marker interfaces? Examples?
*******
26. Difference between string created as new and as literal
what is composition, aggregation and association ?
composition vs inheritance?
How to iterate over hashmap key values ?
What if I return a constant value from hashcode method?
What are the rules of overriding ?
IF a method throws FileNotFoundException in super , can the same method in subclass throws IOException
IF a method throws NullPointerException in super , can the same method in subclass throws ArrayStoreException
Can any class be added to treemap ?
Can you access non static variable in static context?Why or why not ?
23. What is the base class of all exceptions ?
What is bytecode ?
What's the size of character in java ? Why ?
What is JIT ?
How is java secure language?
What are the features of Java language ?
Is java strongly typed ?
How java compiler compiles a java program? What about dependencies?
What should be the file name of java?
Can I write a different filename than class name?
Is empty java source file valid?
Can I print something from a program not having main method?
Why main method is static?
I have two methods of same name , one accepts string , other object , I pass argument as null , which one will be called?
same question , for string and stringbuffer
what if I declare getter , setter without declaring variable?
Is javascript part of java ?
what is constructor?
constructor vs method
is constructor inherited?
can constructor be overloaded?
can constructor be overriden?
does java provides copy constructor?
what is the first statement of any constructor?
Explain how memory is allocated by JVM?
How is java WORA ?
what is the difference between static method and non static method?
Does java support pointers? Why or why not?
How to create a virtual function in java?
Is it necessary to initialize final variable?
Can you declare main method as final?
what is static binding and dynamic binding? Difference?
what is compile time binding and runtime binding?
what is abstraction?
what is encapsulation?
abstraction vs encapsulation?
Give real life examples of abstraction,encapsulation,inheritance.
can a class be abstract and final?
is goto a keyword in java?
is const a keyword in java?
can an interface be final?
can we declare variables in interface?
Can we mark constructor as protected? What will it mean?
What are packages? What are two strategies to group classes in packages?
What is the first line in any class?
What is the order of execution in a class?
What if I import same class twice?
Should I import as java.util.* or java.util.<some class>? Difference?
What is static import?
Which package is imported by default?
Base class for error and exception?
What is exception propagation?
Can an exception be rethrown?
Can a subclass overriding method throw an exception not thrown by superlcass method?
What is intern method?
iteration vs enumeration
can we overload static methods in java
why constructor be final,static,abstract
Multithreading
1. What is a thread ? What is a process ? What's the difference ?
2. How to create a thread ? Which way do  you prefer ? What's the difference between runnable and callable ?
3.multithreading best practices
4. What is volatile keyword ?
5. What is thread safety ? What is race condition? What is deadlock ? What are the conditions for deadlock ? Give an example of deadlock. How to prevent deadlock ? What is livelock ?
6. Semaphore vs mutex vs lock vs synchronized
7. Why wait , notify , notifyAll are declared in Object class ? Why wait and notify should be called from synchronized block ? notify vs notifyAll
8. How to create immutable objects in java ?
9. sleep vs wait vs yeild
10. Write code to solve producer consumer problem.
11.write thread safe singleton
12. how threads are scheduled in java?
13. countdownlatch vs cyclicbarrier
14. How to stop a thread ?
15. what is thread pool ? How to use , why to use ?
16. threadlocal
17. submit vs execute in thread pool
18. readwritelock
19. reentrant lock
20. fork join framework
21. how to ensure sequence in multiple threads
22. start vs run
23. What is Java memory model ?
24. what is thread group ? Should we use it ?
25. green thread , native thread
whole method synchronized vs critical section synchronized ?
Java Collections:
1. What is a collection ? What is collections framework ? What are the benefits ?
2. What is the difference between collection , Collection and Collections ?
3. What are the importatnt interfaces of collections framework? Draw  the diagram for collections framework heirarchy.
4. What is the difference between ArrayList and Vector ?
5. How hashmap , hashset and treemap works ? What is the difference between HashMap , Hashtable , concurrenthashmap?
6. What is the difference between ordered and sorted ? Which two interfaces are used for providing sorting order ?
7. Why map is not part of collections framework ?
8. What Collection doesn't implement Serializable and Cloneable interface ?
9. What is the difference between fail fast and fail safe iterator ?
10. What is copyonwritearraylist and why it is used ?

Spring
1. What is spring ? Why use spring ?
2. What is IoC ? What is DI ? Types of DI ? When to use which ?
3. What are the modules in spring ?
4. What is AOP ? Why use it ?
5. What is spring MVC ?
6. What is lifecycle of bean ?
7. What is beanfactory and application context ? Differences ?
8. What are scopes of bean in spring ? Differences ?
9. Which design patters are used in spring ?
10. What are the new features in spring 4 ?
11. What is bean auto wiring? What are different types of doing that?
12. How will you resolve circular dependency in spring?
13. What is aspect, joinpoint, pointcut, advice, introduction, target?
14. What is weaving? Types?
15. how to integrate hibernate with spring ?
16. What is spring mvc? How to setup spring mvc?
17. how to develop rest web services in spring?
18. What are best practices in spring?
19. What is the difference between n-tier and MVC?
20. How is transaction management done in spring? Types? Prefer?
Difference between @Component, @Repository, @Service ?
15. What is dispatcher servlet?
16. types of IOC container in spring ? Differences ?
17.
18. how spring simplifies jdbc ?
19.
20.
21. different jdbc template ? purpose ?
22. spring aop vs aspectJ aop ?
23. does spring framework supports all join points ?
24. what is front controller class in spring mvc
25. @Controller
26. @RequestMapping
27. @PathVariable
28. ViewResolver ? Types ?
29.
30. How validation in spring ?
31. Benefits of spring tool suite ?
32. What is spring bean ?
33. Bean life cycle ?
33. Different ways of configuring spring bean ?
34.
35. what is context loader listener ?
36. what is multipart resolver and when it's used ?
37. how to handle exceptions in spring  , spring mvc  , sprin jdbc , etc?
38. does spring bean provide thread safety ?
39. can we have multiple spring configuration files ?
40. what is spring mvc interceptor ?
41. what is spring security ?
42. how to inject properties ?
43. how to use collections in spring ?
44.
45. design patterns used in spring ?
46. what is spring xml based configuration and java based configuration and annotation based? difference ? which one you prefer and use ?  (redefine it)
47. are singleton beans thread safe ?
48. Explain @Autowired
49. Explain @Qualifier
50. Explain @Inject
51. Explain @Required
52. DIfferent types of events in spring ?
53. Difference between FileSystemResource , ClassPathREsource
54. What are different implementation/types of ApplicationContext ?
57. what are inner beans ?
58. what are limitations in autowiring ?
59. how to turn on annotation wiring ?
60. what is spring dao ? (??)
61. spring aop target object ?


Hibernate
1. What is hibernate? Why use it? Benefits over JDBC?
2. How to set up hibernate?
3. What is mapping, one to one, etc and how to do it?
4. How inheritance is handled?
5. What is the difference between transient, persistent and detached objects?
6. Explain hibernate cache.
7. What is session,sessionFactory? Are they threadsafe?
8. How transaction management is done in hibernate ?
9. What's the architecture of hibernate?
10. HQL vs SQL?
11. Difference between get and load in hibernate ?
12. Why it's important to provide no argument constructor ?
13. What is the difference between save, persists, saveOrUpdate ?
14. What is named SQL query ?
13. What is the difference between session's lock and update method?
14. Explain second level cache in detail.
15. What is query cache in hibernate?
What is criteria API? Pros and cons?
16. Can we make a hibernate class entity final?
17. What is ORM? What's the use? Examples?
18. How to create sessionFactory?
19. What are POJOs , what's their significance?
20. How to invoke stored procedure in hibernate?
21. What are the types of collections in hibernte?
22. What are the four ORM levels in hibernate?
23. How primary key is created in  hibernate?
24. How can we reattach any detach objects in hibernate?
25. What are different fetching strategies of hibernate?
26. How database table is mapped with java object?
27. What is the use of version property in hibernate?
28. Does hibernate supports polymorphism?
29.
Design Patterns
1. Which design patterns have you used ?
2. What is the difference between factory , abstract factory and builder ?
3. Write code for singleton , observer ?
4. Difference between strategy and state ?
5. What are the best coding practices in Java ?
6. Design ATM , parking lot , wallet , ecommerce.
7. Question on one of the following , singleton , factory , abstract factory , builder , prototype , observer , facade , decorator, dao. Give real life example of these.
8. Code to solve producer consumer problem.
9. What is MVC and n tier ? Why use it ? Difference
10.What are the types of patterns? Differences ?
Design Chess
SQL
1. What is difference between delete and truncate ?
2. What are different types of join ?
3. A question on join , especially self join such as , How to find all employees who are also manager ?
4. How to find second highest salary ?
5. What are indexes ? Types ? Difference ? Why use index ? Pros and cons ?
6. What is primary key , foreign key , unique key , candidate key ? Differences ?
7. What is normalization ? Types ? How to achieve ? What is denormalization ?
8. What is view ? Why use it ?
9. What are types of query (correlated , subquery) ?
10. What are constraints , different type of constraint , when to use which ?
ACID?
Web Services
1. What are web services ? Why use them ?
1. What is service oriented architecture ? Benefits ?
2. What is REST ? Why use it ? What is a resource ?
3. Difference between rest and soap ? When to use which ?
4. Difference between get and post ?    Difference between put and post ?
5.What happens if RestFull resources are accessed by multiple clients ? Do you need to make it thread-safe?
Client server technology
Servlet , JSP
1. What is a servlet ? What are it's advantages ?
2. What is the difference between web server and application server ?
3. How many instances of a servlet are created? Are servlet thread safe?
4. What is the difference between servletcontext and servletconfig object ?
5. How can we create deadlock in servlet ?
6. How to do session management ?
7. What is the life cycle of a servlet ?
8. What is the difference between URL encoding and URL rewriting ?
9. How does cookies work ?
10. What is the difference between get and post ?
OS:
1. What is the difference between a process and a thread ?
2. What is a semaphore , mutex , lock ? Differences ?
3.  What is virtual memory ?
4. What is paging ? What is segmentation fault ?
5. What is banker's algorithm ?
6. When does thrasing occurs ?
7. What is deadlock ? What are the conditions for it ? How to prevent it ?
8. What are the types of scheduler ?
9. What is belady's anomaly ?
10. What is dining philosopher problem and solution ?
How ftp works
Linux:
Grep
Others
xml vs json
Networking
What is IP address?
What is MAC address?
What is MAC layer?
OSI?
TCP?
Network Address Translation?
DNS?
Checksum error correction
3 bit parity
HTML , Javascript , CSS , Web
What is HTML5 ?
What is jquery ? Why use it ?
What is the difference bewtween '==' and '===' ?
What is CSS ? Advantages ?
What is css box model ?
What is ajax ? Why and how to use it?
What is closure ? Give example?
Can you access cookie using javascript ?
How to redirect url using javascript ?
What is the use of void(0) ?
Puzzles100 floors and 2 eggs
Hats on three men , in a line , tell color
Rickety bridge , 1,2,7,10 min , one lantern , max two people on bridge
switches outside a room , how to find which one is for bulb
2 candles each burn in 30 min , how to measure 45 min
Ants are moving from corners of equilateral traingle. Probability won't collide ?
Camel and banana
100 doors , flipped as you pass
5 pirates , 100 gold coin , strategy
country people want only boy , ratio of boys to girls
100 trucks , 1000 mile...
50 red marbles , 50 blue marbles , 2 jars ,  one jar selected , one marble selected , maxiimize prob. of red marble
How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?
A duck that is being chased by a fox saves itself by sitting at the center of circular pond of radius r. The duck can fly from land but cannot fly from the water. Furthermore, the fox cannot swim. The fox is four times faster than the duck. Assuming that the duck and fox are perfectly smart, is it possible for the duck to ever reach the edge of the pond and fly away to its escape from the ground?
There are n houses in a row , we have to paint them in R,G,B , no two house can have same clor , each paint has cost associated , find min cost
Gold bar puzzle
25 Horses puzzle
Max number on sphere which are equidistant?
How many points can be equidistant to each other?

HR
Tell me abt yourself
Why <this company>?
Your weaknesses?
5 years?
Any question?
Why to hire you?

General
Trending Technologies




****************Top 10******************************8

Solve each problem in every possible way.
Top 20 DS , Algo ,Coding , Bit Magic
1. Write code to find loop in linkedlist , reverse a linkedlist , is Palindrome
2. Find LCA in a binary tree.
3. Do DFS ,BFS,inorder , preorder ,postorder ,zigzag in tree. (recursive +iterative)
4. A question on sorting among bubble , quick , merge
5. How to find middle element or kth element from end in a linked list ?
6. In an integer array, there is 1 to 100 number, out of one is duplicate, how to find ?
7. Write code to reverse a string without using any API.
8. Write a program to find diameter , height of tree.
9. How will you implement a dictionary ?
10. Implement LRU.
11. Djikstra , prim
12. Find number of set bits.
13. Check number is power of 2.
14. How to search in rotated array ?
15. Search in a sorted 2d matrix.
16. Print 2d matrix in spiral
17. Find kth largest element in array
18. Implement stack using queue , queue using stack , two stack using an array.
19. Check string/integer is palindrome.
20. A DP problem , such as find maximum subarray , longest palindrome substring , best time to buy sell stock
Top 10 Java
1. What is OOPS ?
2. How hashmap works in Java ? Difference between hashmap and hashtable ? What will happen if I put a key which already exists in hashmap ?
3. What is an interface ? Difference between interface and abstract class ? When to use which ?
4. Overloading vs overriding ?
5. Why string is immutable ?
6. What is difference between arraylist and linkedlist ?
7. What is difference between JDK, JRE and JVM ?
8. Why use getters and setters ?
9. Does Java support multiple inheritance ?
10. What are the types of Exceptions ? How are they different ?
Top 10 Multithreading
1. What is a thread ? What is a process ? What's the difference ?
2. How to create a thread ? Which way do  you prefer ? What's the difference between runnable and callable ?
3.multithreading best practices
4. What is volatile keyword ?
5. What is thread safety ? What is race condition? What is deadlock ? What are the conditions for deadlock ? Give an example of deadlock. How to prevent deadlock ? What is livelock ?
6. Semaphore vs mutex vs lock vs synchronized
7. Why wait , notify , notifyAll are declared in Object class ? Why wait and notify should be called from synchronized block ? notify vs notifyAll ?
8. How to create immutable objects in java ?
9. sleep vs wait vs yield
10. Write code to solve producer consumer problem.
Top 10 Collections
  1. What is a collection ? What is collections framework ? What are the benefits ?
  2. What is the difference between collection , Collection and Collections ?
  3. What are the importatnt interfaces of collections framework? Draw the diagram for collections framework heirarchy.
  4. What is the difference between ArrayList and Vector ?
  5. How hashmap , hashset and treemap works ? What is the difference between HashMap , Hashtable , concurrenthashmap?
  6. What is the difference between ordered and sorted ? Which two interfaces are used for providing sorting order ?
  7. Why map is not part of collections framework ?
  8. What Collection doesn't implement Serializable and Cloneable interface ?
  9. What is the difference between fail fast and fail safe iterator ?
  10. What is copyonwritearraylist and why it is used ?
Spring
1. What is spring ? Why use spring ?
2. What is IoC ? What is DI ? Types of DI ? When to use which ?
3. What are the modules in spring ?
4. What is AOP ? Why use it ?
5. What is spring MVC ?
6. What is lifecycle of bean ?
7. What is beanfactory and application context ? Differences ?
8. What are scopes of bean in spring ? Differences ?
9. Which design patters are used in spring ?
10. What are the new features in spring 4 ?
Spring MVC
1.  What is spring mvc ? Explain the architecture ?


Hibernate
1. What is hibernate ? Why use it ? Benefits over JDBC ?
2. How to set up hibernate ?
3. Difference between get and load in hibernate ?
4. What is session , sessionFactory? Are they threadsafe?
5. What is the difference between transient , persistent and detached objects ?
6. Explain hibernate cache.
7. Why it's important to provide no argument constructor ?
8. What is mapping , one to one , etc and how to do it ?
9. How inheritance is handled ?
10. How transaction management is done in hibernate ?
Design Patterns
1. Which design patterns have you used ?
2. What is the difference between factory , abstract factory and builder ?
3. Write code for singleton , observer ?
4. Difference between strategy and state ?
5. What are the best coding practices in Java ?
6. Design ATM , parking lot , wallet , ecommerce.
7. Question on one of the following , singleton , factory , abstract factory , builder , prototype , observer , facade , decorator, dao. Give real life example of these.
8. Code to solve producer consumer problem.
9. What is MVC and n tier ? Why use it ? Difference
10.What are the types of patterns? Differences ?
SQL
1. What is difference between delete and truncate ?
2. What are different types of join ?
3. A question on join , especially self join such as , How to find all employees who are also manager ?
4. How to find second highest salary ?
5. What are indexes ? Types ? Difference ? Why use index ? Pros and cons ?
6. What is primary key , foreign key , unique key , candidate key ? Differences ?
7. What is normalization ? Types ? How to achieve ? What is denormalization ?
8. What is view ? Why use it ?
9. What are types of query (correlated , subquery) ?
10. What are constraints , different type of constraint , when to use which ?
  1. What are web services ? Why use them ?
  2. What is service oriented architecture ? Benefits ?
  3. What is REST ? Characteristics ? Why use it ? What are the http methods supported by REST ? What is a resource ?
  4. Difference between rest and soap ? When to use which ?
  5. Difference between get and post ?    Difference between put and post ?
  6. What happens if RestFull resources are accessed by multiple clients ? Do you need to make it thread-safe?
  7. How to use web services with spring ?
  8. What is URI ? URI vs URL ?
  9. What is statelessness ? Pros and cons ?
  10. What are the components of REST request and response ?
Servlet , JSP
1. What is a servlet ? What are it's advantages ?
2. What is the difference between web server and application server ?
3. How many instances of a servlet are created? Are servlet thread safe?
4. What is the difference between servletcontext and servletconfig object ?
5. How can we create deadlock in servlet ?
6. How to do session management ?
7. What is the life cycle of a servlet ?
8. What is the difference between URL encoding and URL rewriting ?
9. How does cookies work ?
10. What is the difference between get and post ?

OS:
1. What is the difference between a process and a thread ?
2. What is a semaphore , mutex , lock ? Differences ?
3.  What is virtual memory ?
4. What is paging ? What is segmentation fault ?
5. What is banker's algorithm ?
6. When does thrasing occurs ?
7. What is deadlock ? What are the conditions for it ? How to prevent it ?
8. What are the types of scheduler ?
9. What is belady's anomaly ?
10. What is dining philosopher problem and solution ?

HTML , Javascript , CSS , Web
  1. What is HTML5 ?
  2. What is jquery ? Why use it ?
  3. What is the difference bewtween '==' and '===' ?
  4. What is CSS ? Advantages ?
  5. What is css box model ?
  6. What is ajax ? Why and how to use it?
  7. What is closure ? Give example
  8. Can you access cookie using javascript ?
  9. How to redirect url using javascript ?
  10. What is the use of void(0) ?

*******************************************************
ANSWERS
*******************************************************
DS , Algo ,Coding , Bit Magic
1. Write code to find loop in linkedlist , reverse a linkedlist , is Palindrome
2. Find LCA in a binary tree.
3. Do DFS ,BFS,inorder , preorder ,postorder ,zigzag in tree. (recursive +iterative)
4. A question on sorting among bubble , quick , merge
5. How to find middle element or kth element from end in a linked list ?
6. In an integer array, there is 1 to 100 number, out of one is duplicate, how to find ?
7. Write code to reverse a string without using any API.
8. Write a program to find diameter , height of tree.
9. How will you implement a dictionary ?
10. Implement LRU.
11. Djikstra , prim
12. Find number of set bits.
13. Check number is power of 2.
14. How to search in rotated array ?
15. Search in a sorted 2d matrix.
16. Print 2d matrix in spiral
17. Find kth largest element in array
18. Implement stack using queue , queue using stack , two stack using an array.
19. Check string/integer is palindrome.
20. A DP problem , such as find maximum subarray , longest palindrome substring , best time to buy sell stock

Spring
1. What is spring ? Why use spring ?
Spring is an IoC (Inversion of Control) framework and container. It uses DI(Dependency Injection) to instantiate objects. It provides option to integrate with a lots of other frameworks such as struts , hibernate , etc.
Spring provides many benefits :
a) It provides IoC container which leads to loose coupled code. Loosely coupled code has many benefits , it's easy to modify , easy to test.
b) It is very less intrusive and most of the functionalites can be achieved by just using POJOs.
c) Most of the functionalites are now can be achieved by using annotation which makes development very easy.
d) It provides easy integration to lot of other frameworks such as hibernate ,  redis , struts , etc.
e) It provides MVC support.
f) It provides better exception handling.
f) It provides templates which reduces a lot of boilerplate code.
2. What is IoC ? What is DI ? Types of DI ? When to use which ?
IoC stands for Inversion of Control. It refers to the change in flow of program from code to some external entity such as xml. In this situation objects are instatiated by an external entity and then injected into the code thus creating loosely coupled code.
DI stands for Dependency Injection. It's a way to achieve inversion of control. In this , objects are injected by some external entity such as xml. There are two types of DI:
a)
3. What are the modules in spring ?
4. What is AOP ? Why use it ?
5. What is spring MVC ?
6. What is lifecycle of bean ?
7. What is beanfactory and application context ? Differences ?
8. What are scopes of bean in spring ? Differences ?
9. Which design patters are used in spring ?
10. What are the new features in spring 4 ?
Hibernate
1. What is hibernate ? Why use it ?
2. How to set up hibernate ?
3. Difference between get and load in hibernate ?
4. What is session , sessionFactory ? Are they threadsafe ?
5. What is the difference between transient , persistent and detached objects ?
6. Explain hibernate cache.
7. Why it's important to provide no argument constructor ?
8. What is mapping , one to one , etc and how to do it ?
9. How inheritance is handled ?
10.
Design Patterns
1. Which design patterns have you used ?
2. What is the difference between factory , abstract factory and builder ?
3. Write code for singleton , observer ?
4. Difference between strategy and state ?
5. What are the best coding practices in Java ?
6. Design ATM , parking lot , wallet , ecommerce.
7. Question on one of the following , singleton , factory , abstract factory , builder , prototype , observer , facade , decorator. Give real life example of these.
8. Code to solve producer consumer problem.
9. What is MVC and n tier ? Why use it ? Difference
10.
SQL
1. What is difference between delete and truncate ?
2. What are different types of join ?
3. A question on join , especially self join such as , How to find all employees who are also manager ?
4. How to find second highest salary ?
5. What are indexes ? Types ? Difference ? Why use index ? Pros and cons ?
6. What is primary key , foreign key , unique key , candidate key ? Differences ?
7. What is normalization ? Types ? How to achieve ? What is denormalization ?
8. What is view ? Why use it ?
9. What are types of query (correlated , subquery) ?
10. What are constraints , different type of constraint , when to use which ?
Web Services
1. What is service oriented architecture ? Benefits ?
2. What is REST ? Why use it ?
3. Difference between rest and soap ? When to use which ?
4. Difference between get and post ?
Servlet , JSP
1.
OS:
What is the difference between a process and a thread ?
What is a semaphore , mutex , lock ? Differences ?
HTML , Javascript , CSS , Web





***************************************Top 10 ends **********************




Posted by at No comments:

Saturday 13 February 2016

DSA All

DS , Algo ,Bit Magic (Solve each problem in every possible way)
Write code to find loop in linkedlist.
Write code to reverse a linkedlist.
Write code to reverse a string without using any API.
Implement Djikstra.
Write code for  DFS,BFS,inorder,preorder,postorder,zigzag in tree.
Implement quick sort.
Implement merge sort.
Implement autosuggest feature from a list of words.
Implement LRU.
Check if a tree is BST?
Print numbers in order using two threads.
Write code to find diameter, height of tree(or binary tree?).
Write code to check if a number is power of 2.
Write code to search a number in rotated array.
Write code to check if a number is prime.
Find LCA(Lowest Common Ancestor) in a binary tree.
12. Write code to find number of set bits in an integer.
5. Write code to find kth element from end in a linked list ?
6. Write code to find the missing number in an integer array having 1 to 100 in random order except a number.
10. Write code to check if linkedlist is palindrome.
12. Implement Prim.
15. Write code to search a number in a sorted 2d matrix.
16. Write code to print 2d matrix in spiral order.
17. Write code to find kth largest element in an array.
18. Implement stack using queue.
19. Implement queue using stack.
20. Implement two stack using an array.
21. Implement three stacks using an array.
19. Write code to check integer is palindrome.
19. Write code to check string is palindrome.
20. Write code to find maximum continous subarray in an array.
21. Write code to find longest palindrome substring in a string.
22. Write code to find best time to buy sell stock.
22. Write code to swap two numbers.
23. Write code to find sum of digits
24. Write code to reverse an integer.
24. Write code to print first n numbers infibonacci series.
25. Write code to print nth fibonacci number.
25. Write code to add two numbers represented by a linked list.
26. Write code for bubble sort.
27. Implement radix sort.
28. Implement counting sort.
29. Implement insertion sort.
30. Implement selection sort.
31. Implement heap sort.
32. Implement bucket sort.
33. Write code to find first repeated character in a string.
34. Write code to find first unique character in a string.
How to find middle element of linkedlist in one pass?
Write code to remove duplicates from an array.
Implement BST.
Implement doubly linked list.
Implement doubly linked list using single pointer.
Write code to convert decimal to binary.
Write code to sort a map by value.
Write code to find common elements in two arrays.
Find longest substring without repeating characters.
Determine whether a point lies inside a triangle.
Nuts and bolts problem.
What is the probability that knight stays inside the chess board?
Implement stack using likedlist.
Implement queue using linkedlist.
Check for balanced paranthesis in an expression.
Sort an array containing only 0 and 1.
Sort a linkedlist containing 0,1,2.
Minimum number of platforms required at railway station.
convert word to another , one time one character , from a list of words.
Break string into dictionary words.
Find seed of a number. A number X is seed of Y if multiplying X by it's digits equates to Y.
Finds pairs of numbers with difference k  from an unsorted array.
Find number of trailing zeros in a number factorial.
Given an array containing 0 and 1 , find the largest subarray cotaining equal number of 0 and 1.
Sort an array of elements by decreasing order of frequency.
Given an array of words , group all anagrams in set
Find the min element in a sorted rotated array.
Delete all leaves from a binary tree.
Find two elements in an array whose sum is closest to zero.
Given two rectangles if they overlap or not (Imp)Find max sub square submatrix in a 2d matrix of 0 and 1 with all 1.
Minimum coin problem
Rotate an array by k
Find the level of a given node in a binary tree
Implement heap sort
Implement priority queue.
Find difference in the sum of nodes at odd level and nodes at even level of  a binary tree.
Check for children sum property of a binary tree.
Inorder predecessor in a binary tree
Inorder successor in a binary tree.
Rotate linked list by k nodes
Sort an array of 0,1,2.
Find pair of elements in an array whose sum is equal to given number.
Check whether two strings are anagram.
Given a  linked list , each node has two pointers , one point to next , another to some random node , How to copy it  ?
Get intersection point of two linked lists. (imp)
count nodes in a tree
determine if two binary trees are identical?
Implement binary search algorithm(imp)
sort an almost sorted array with two elements swapped
merge two sorted array without using extra space , assuming first array has enough space
Find minimum distance between two elements in an array
Print all the leaders in an array.
Given a 2d matrix m of 0 and 1 , if m[i][j] is 1 , fill row i and col j with 1
Replac each element of an array with next greatest element.
Find row with max 1 in sorted matrix
Find the number occuring odd number of times in an array , rest occur even number of times.
Given k sorted arrays of size n , merge them.
Find all pythogorean triplets in an array.
Convert sorted array to balanced BST.
Find LIS contigous.
Find LIS non contigous.
Find sub array whose sum equals given number.
Find max diff. between two elements in an array such that larger appears after smaller.
Find majority(occurs more than half) element in an array in O(n).
Even numbers at even pos , odd at odd in an array
Find union and intersection of two arrays.
Find smallest positive number missing from an array.
Shift zeros to end of array
Reverse linkedlist in group of k
Remove spaces from a sentence.
Reverse each word of a sentence
multiply two numbers using min. number of additions
detect cycle in graph
print bottom view of binary tree
print top view of binary treeadd two integers without using +
randomized quick sort
In a 2d matrix , a sub square matrix is painted , find minimal/optimal cost of painting the rest using a fixed block. which block to use ?
Floyd WarshallA 2d matrix containing 0,1,2 , 0 -> empty orange , 1-> fresh orange , 2-> rotten orange , how much time so that all are rotten , a rotten orane will rot adjacent (not diagonal) in one time frame.
Given a binary tree, n and k , find sum of all nodes which are k nodes away from node n.
mirror a binary tree
check if two binary trees are mirror
Convert BST to DLL.
check binary tree is bst
convert sentence like 'these are twelve pens and two shirts. convert it to 'these are 12 pens and 2 shirts'. Inline
Given linkedlist of moves of 2 players on tic tac toe , find who won
Given pile of 9 objects , Pick 1,2,or 3. 2 Players , last one to pick is looser. Give winning strategy.
Given stream of integers , give me median at any time.
Construct BST from pre and inorder
Rod cutting problem
Deletion in bst
Implement using BST
How many bits need to change to convert one num to other?
Check MSB is 0/1 ?
T9 dictionary implement

*****************************ANSWERS******************************

 1. Write code to find loop in linkedlist 

package dsa;


public class LoopInLinkedList {
 
 class Node{
  int data;
  Node next;
  
  Node(int data){
   this.data=data;
  }
 }
 
 Node head;
 Node tail;
 
 void add(int i){
  Node temp = new Node(i);
  if(head==null){
   head = temp;
  }else{
   temp.next=head;
   head=temp;
  }
 }
 void createLoop(){
  Node temp = new Node(1);
  head=temp;
  tail=temp;
  temp = new Node(2);
  Node node2=temp;
  tail.next=temp;
  tail=temp;
  temp = new Node(3);
  tail.next=temp;
  tail=temp;
  temp = new Node(4);
  tail.next=temp;
  tail=temp;
  temp = new Node(5);
  tail.next=node2;
  tail=temp;
  
 }

 void findLoop(){
  Node slow = head;
  Node fast = head.next;
  
  while(true){
   slow = slow.next;
   fast = fast.next.next;
   if(slow==fast){
    System.out.println("Loop found");
    break;
   }
  }
 }
 
 public static void main(String[] args) {
  LoopInLinkedList l = new LoopInLinkedList();
  l.createLoop();
  l.findLoop();
 }

}

2. Write code to reverse a linkedlist

 3. Write code to reverse a string without using any API.
package strings;


public class ReverseString {
 
 static String reverse1(String str){
  StringBuilder sb = new StringBuilder(str);
  return sb.reverse().toString();
 }
 
 static String reverse2(String str){
  char[] arr = str.toCharArray();
  char temp='a';
  for(int i=0;i<=arr.length/2;i++){
   temp = arr[i];
   arr[i]=arr[arr.length-1-i];
   arr[arr.length-1-i]=temp;
  }
  return new String(arr);
 }
 
 public static void main(String[] args) {
  System.out.println(reverse1("Hello how are you?"));
  System.out.println(reverse2("Hello how are you?"));
 }

}
4. Implement Djikstra.
5. Write code for  DFS,BFS,inorder,preorder,postorder,zigzag in tree.
6. Implement quick sort.
7. Implement merge sort.
8. Implement autosuggest feature from a list of words.
9. Implement LRU.
10. Write code to find diameter, height of tree(or binary tree?).
Posted by at No comments:

Project- ClearPath Forward- UNISYS-2013-14

A mainframe solution
What is mainframe ?
Technologies Used :
Java
Liferay
Hibernate
MySQL
What is sPar , what is virtualization ?




Posted by at No comments:

Project- Physics engine

Famo.us
three.js
Ammo.js
WebGL

later scrapped
Posted by at No comments:

Project-Eclipse Plug-in development

Explain something about it.
Posted by at No comments:

Project-KBO

It's a server side project. It provide a service to all the samsung tv users in Korea. KBO stands for Korean Baseball Organization.
Technology used :
Java 6
Spring 3.2  including Spring MVC
Ibatis , which I should change to Hibernate I guess
MySQL 5
Redis Cache
Apache Tomcat 7
Spring Rest Service
JSON
The project consists of different modules :
FTP Batch: This batch runs every 2 minutes and read the data provided by third party in the form of CSV files to a ftp server and insert it into database using Hibernate.
Redis Batch: This batch consists of three threads :
  1. KBO Config : Runs every 2 seconds . Check KBO configuration.
  2. KBO Basic Info : Fetches basic information about current matches and put them in the redis cache server.
  3. KBO Detail Info : Fetches detailed information about current matches and put them in the redis cache server.


Uses:

Filter is used for logging and validating headers, ContainerRequestFilter of jersey is used.
Another filter to log the response , ContainerResponseFilter is used.
Filter for authentication is also used,
















Posted by at No comments:

Web Services All


What are web services ? Why use them ?
What is service oriented architecture ? Benefits ?
What is REST ? Characteristics ? Why use it ? What are the http methods supported by REST ? What is a resource ?
Difference between rest and soap ? When to use which ?
Difference between get and post ?    Difference between put and post ?
What happens if RestFull resources are accessed by multiple clients ? Do you need to make it thread-safe?
How to use web services with spring?
What is URI ? URI vs URL ?
What is statelessness ? Pros and cons ?
What are the components of REST request and response ?
*******************************************************       
                ANSWERS  
*******************************************************
What are web services ? Why use them ?
Web service is a mechanism by which two programs communicate over web.
Web services help in building scalable, dynamic, distributed software system.
According to Oracle:
Web services are client and server applications that communicate over the World Wide Web’s (WWW) HyperText Transfer Protocol (HTTP). As described by the World Wide Web Consortium (W3C), web services provide a standard means of interoperating between software applications running on a variety of platforms and frameworks. Web services are characterized by their great interoperability and extensibility, as well as their machine-processable descriptions, thanks to the use of XML. Web services can be combined in a loosely coupled way to achieve complex operations. Programs providing simple services can interact with each other to deliver sophisticated added-value services.
What is service oriented architecture? Benefits?
http://www.indiawebdevelopers.com/resource_center/articles/soa.html
When to use
What is REST? Characteristics? Why use it? What are RESTful web services? What are the http methods supported by REST? What is a resource?
REST stands for representational state transfer. It's a software architectural style for world wide web.
REST has following properties/constraints:
a) Client Server Architecture
b) Stateless
c) Cacheable
d) Layered
e) Uniform Interface
f) Code on Demand(optional)
It has many benefits such as :
a) Stateless, lightweight
b) Simple,  efficient, easy to implement architecture.

Restful webservices are web services which follow RESTful architecture. It is HTTP-based and and functionalites are exposed as resources via URI and HTTP-based verbs such as GET,POST,PUT,DELETE,HEAD,TRACE are used to create/modify resources.
Resource is similar to an object in oop except that it's accessed via HTTP verbs such as GET,POST,PUT,etc. (????)
I think any functionality or object exposed via web services is a resource(??)
I think this is correct: Any information that can be named can be a resource, a document or image, etc.
From Fielding's dissertation:
The key abstraction of information in REST is a resource. Any information that can be named can be a resource: a document or image, a temporal service (e.g. "today's weather in Los Angeles"), a collection of other resources, a non-virtual object (e.g. a person), and so on. In other words, any concept that might be the target of an author's hypertext reference must fit within the definition of a resource. A resource is a conceptual mapping to a set of entities, not the entity that corresponds to the mapping at any particular point in time.
Difference between rest and soap ? When to use which ?
a) Rest is lightweight compared to soap.
Soap tightly couple client and server while rest keeps them loosely coupled. Any changes in either side leads to change in soap. There is no wsdl, uddi in rest.
b) Rest can be used with xml or json while soap is limited to xml. JSON is human readable, easily parseable, close to JS.
c) Rest works on http while soap has it's own protocol.
d) SOAP provides more control than REST. Depending on the requirements , if not so much sophisticated implementation is required , REST can be used.
5.) Soap provides better security.
Difference between get and post? Difference between put and post?
a) GET is non-idempotent i.e, it doesn't changes the resource while POST is idempotent.
Is get vs post same in web services as in http ??Put and Post are very similar in rest. Put is used to create a new resource while post is used to edit any changes. Put is idempotent and POST is not.
What happens if RestFull resources are accessed by multiple clients ? Do you need to make it thread-safe?
For every request a new instance of resource is created. So, restful resources are inherently thread safe.
How to use web services with spring ?
Web services can be easily used with spring MVC.  Link to example.
What is URI? URI vs URL?
URI stands for Uniform Resource Identifier, it is the complete path of the resource. URL stands for Unifrom Resource Locator. URL tell the server location only. URL is part of URI.
What is statelessness? Pros and cons?
Statelessness refers to the feature that a component doesn't remember anything about the last request, i.e, it doesn't maintain any state. There is no difference between new request from a different machine or same machine.
Statelessness helps in developing lightweight, fast, distributed system.
Benefits:
a) Less memory overhead
b) No session related issues
c) Easy sharing of urls
d) Easy to develop scalable,distributed system because syn is not required across servers.
What are the components of REST request and response?
REST request and response is based on client server architecture. Internet is an example of RESTful architecture. It uses HTTP based verbs to perform any action over HTTP.


**************Unranked**********
High
Web services security (http://www.tutorialspoint.com/webservices/web_services_security.htm)
What is Oauth?
why rest is called so?
Can rest be used over soap or vice versa?
What is jersey, JAX-RS? Why use them?
What is idempotent?
How to test web services? Avg 

Low
What was before web services? (http://stackoverflow.com/questions/3028214/what-came-before-web-services-and-soa)





*****************************ANSWERED QUESIONS*******************
What are web services ? Why use them ?
What is service oriented architecture ? Benefits ?
What is REST ? Characteristics ? Why use it ? What are the http methods supported by REST ? What is a resource ?
Difference between rest and soap ? When to use which ?
Difference between get and post?Difference between put and post ?
What happens if RestFul resources are accessed by multiple clients ? Do you need to make it thread-safe?
How to use web services with spring?
What is URI ? URI vs URL ?
What is statelessness ? Pros and cons ?

What are the components of REST request and response ?
*********************************************************************************

Useful Links:

http://rest.elkstein.org
https://dzone.com/articles/web-services-architecture
http://programmers.stackexchange.com/questions/99389/how-do-i-convince-my-boss-to-use-rest-over-soap
What are web services?
What are the features of web services?
What the components of a Web Service?
How Does a Web Service Work?
What is the purpose of XML in a web service?
What is the purpose of SOAP in a web service?
What is the purpose of WSDL in a web service?
What are the benefits of Web Services?
What do you mean by Interoperability of Web Services?
What do you mean by loosely coupled architecture of Web services?
Do Web services supports Remote Procedure Calls(RPCs)?
What are the behavioral characteristics of web services?
What are the benefits of having XML based WEB services?
What is the benefit of a Web services being loosely coupled?
What is Synchronicity?
What are the core Roles in Web Service architecture?
What is the purpose of Service Provider in Web Service architecture?
What is the purpose of Service Requestor in Web Service architecture?
What is the purpose of Service Registry in Web Service architecture?
What are the core layers in Web Service Protocol Stack?
What is the purpose of Service Transport layer in Web Service Protocol Stack?
What is the purpose of XML Messaging layer in Web Service Protocol Stack?
What is the purpose of Service Description layer in Web Service Protocol Stack?
What is the purpose of Service Discovery layer in Web Service Protocol Stack?
What HTTP stands for?
What is HTTP?
What BEEP stands for?
What is BEEP?
What is XML-RPC?
How request is sent in XML-RPC?
How response is sent in XML-RPC?
What are the features of XML-RPC?
What SOAP stands for?
What is SOAP?
What are the features of SOAP?
Is SOAP platform independent?
What WSDL stands for?
What is WSDL?
What are the features of WSDL?
What UDDI stands for?
What is UDDI?
What are the features of UDDI?
What are the primary security issues with web services?
Which component of Web service describes interfaces to web services?
Which language UDDI uses?
Is XML-RPC is platform-dependent?
If a client sends an XML request to a server, can we ensure that the communication remains confidential?
If a client connects to a web service, how do we identify the user? Is the user authorized to use the service?
What do you mean by Web services manageability?

How to handle Network security threats in Web services?

 What is a Web Service?
What are the advantages of Web Services?
What are different types of Web Services?
What is SOAP?
What are advantages of SOAP Web Services?
What are disadvantages of SOAP Web Services?
What is WSDL?
What are different components of WSDL?
What is UDDI?
What is difference between Top Down and Bottom Up approach in SOAP Web Services?
What is REST Web Services?
What are advantages of REST web services?
What are disadvantages of REST web services?
What is a Resource in Restful web services?
What are different HTTP Methods supported in Restful Web Services?
Compare SOAP and REST web services?
What are different ways to test web services?
Can we maintain user session in web services?
What is difference between SOA and Web Services?
What is the use of Accept and Content-Type Headers in HTTP Request?
How would you choose between SOAP and REST web services?
What is JAX-WS API?
Name some frameworks in Java to implement SOAP web services?
Name important annotations used in JAX-WS API?
What is use of javax.xml.ws.Endpoint class?
What is the difference between RPC Style and Document Style SOAP web Services?
How to get WSDL file of a SOAP web service?
What is sun-jaxws.xml file?
What is JAX-RS API?
Name some implementations of JAX-RS API?
What is wsimport utility?
Name important annotations used in JAX-RS API?
What is the use of @XmlRootElement annotation?

How to set different status code in HTTP response?

 1) Define Web Service?

 A web service is a kind of software that is accessible on the Internet. It makes use of the XML messaging system and offers an easy to understand, interface for the end users.
2) What is new in this field for past few years?

 The initiation of XML in this field is the advancement that provides web service a single language to communicate in between the RPCs, web services and their directories.

 3) Give me an example of real web service?

 One example of web services is IBM Web Services browser. You can get it from IBM Alphaworks site. This browser shows various demos related to web services. Basically web services can be used with the help of SOAP, WSDL, and UDDI . All these, provide a plug-and-play interface for using web services such as stock-quote service, a traffic-report service,  weather service etc.

 4) How you define web service protocol stack?

 It is basically set of various protocols that can be used to explore and execute web services. The entire stack has four layers i.e. Service Transport, XML Messaging, Service Description and Service Discovery.

 5) Can you define each of these layers of protocol stack?

 The Service Transport layer transfer messages between different applications, such as HTTP, SMTP, FTP, and Blocks Extensible Exchange Protocol (BEEP). The XML Messaging layer encodes messages in XML format so that messages can be understood at each end, such as XML-RPC and SOAP. The Service Description layer describes the user interface to a web service, such as WSDL. The Service Discovery layer centralizes services to a common registry and offer simple publish functionality, such as UDDI.

 6) Define XML – RPC?

 It is a protocol that makes use of XML messages to do Remote Procedure Calls.

 7) Define SOAP?

 SOAP is an XML based protocol to transfer between computers.
8) Define WSDL?
It means Web Services Description Language. It is basically the service description layer in the web service protocol stock. The Service Description layer describes the user interface to a web service.

 9) What kind of security is needed for web services?

 Image for Web Services
Web Services
The security level for web services should be more than that of what we say Secure Socket Layer (SSL). This level of security can be only achieved from Entrust Secure Transaction Platform. Web services need this level of security to ensure reliable transactions and secure confidential information .

 10) Do you have any idea about foundation security services?

 As implies from its name, these services are the foundation or basics of integration, authentication, authorization, digital signatures and encryption processes.

 11) Define Entrust Identification Service?

 Entrust Identification Service comes from the Entrust Security Transaction Platform. This platform allows companies to control the identities that are trusted to perform transactions for Web services transactions.

 12) What UDDI means?

 UDDI stands for Universal, Description, Discovery, and Integration. It is the discovery layer in the web services protocol stack.

 13) Define Entrust Entitlements Service?

 This service verifies entities that attempt to access a web service. For Example, the authentication service, the Entitlements Service ensures security in business operations.

 14) Define Entrust Privacy Service?

 As its name implies, it deals with security and confidentiality. This service encrypts data to ensure that only concerned parties can access the data.

 15) What do you mean by PKI?

 It means Public-Key Infrastructure.

 16) What tools are used to test a web service?

 I have used SoapUI for SOAP WS and Firefox poster plugin for RESTFul Services.

 17) Differentiate between a SOA and a Web service?

 SOA is a design and architecture to implement other services. SOA can be easily implemented using various protocols such as HTTP, HTTPS, JMS, SMTP, RMI, IIOP, RPC etc. While Web service, itself is an implemented technology. In fact one can implement SOA using the web service.

 18) Discuss various approaches to develop SOAP based web service?

 We can develop SOAP based web service with two different types of approaches such as contract-first and contract-last. In the first approach, the contract is defined first and then the classes are derived from the contract while in the later one, the classes are defined first and then the contract is derived from these classes.

 19) If you have to choose one approach, then what will be your choice?

 In my point of view, the first approach that is the contract-first approach is more feasible as compared to the second one but still it depends on other factors too.

 20) Is there any special application required to access web service?

 No, you don’t need to install any special application to access web service. You can access web service from any application that supports XML based object request and response.

 21) Can you name few free and commercial implementations for web services?

 The implementations I know are Apache SOAP, JAX-WS Reference Implementation, JAX-RS Reference Implementation, Metro, Apache CXF, MS.NET and Java 6.

 22) Name browser that allows access to web service?

 JavaScript XmlHttpRequest object is required to access web service via browsers. The browsers that support this object are Internet Explorer, Safari and Mozilla-based browsers like FireFox.

 23) What is REST?

 REST stands for Representational State Transfer. REST itself is not a standard, while it uses various standards such as HTTP, URL, XML/HTML/GIF/JPEG (Resource Representations) and text/xml, text/html, image/gif, image/jpeg, etc (MIME Types).

 24) How one can provide API to users?

 To provide an API to the users, one can easily do this with an “open table”. All you need to do is to write open table which is basically an XML schema that point to a web service.

 25) Name the various communication channels in web service?

 Web service is integrated with three protocols such as HTTP/POST, HTTP/GET, and SOAP. It provides three different communication channels to clients. Client can choose any communication method as per requirements.

 26) How can you document web service?

 Web services are contemplated as self-documenting because they provide entire information regarding the available methods and parameters used for XML based standard, known as WSDL. One can also provide more information to explain web services via their own WebService and WebMethod attributes.

 27) What are the situations, when we need ASP.NET web services?

 ASP.NET web services are used when one need to implement three tier architecture in a web service. It allows handy ways to use middle tier components through internet. The main advantage of .NET Web services is that they are capable enough to communicate across firewalls because they use SOAP as transport protocol.

 28) What are distributed technologies?

 The increasing ratio of distributed applications has raised demand for distributed technologies. It allows segmenting of application units and transferring them to different computers on different networks.

 29) Differentiate between web services, CORBA and DCOM?

 Web services transfer/receive messages to/from application respectively, via HTTP protocol. It uses XML to encode data.

 CORBA and DCOM transfer/receive messages to/from application respectively, via non-standard protocols such as IIOP and RPC.

 30) Can you tell few benefits of web services?

 The biggest advantage of web service is that is supported by wide variety of platforms. Moreover, in near future, web services may spread its boundary and enhance new methods that will provide ease to clients. The enhancement will not affect the clients, even if they offer old methods and parameters.

 31) Can you name some standards used in web services?

 The standards used in web services are WSDL (used to create interface definition), SOAP (used to structure data), HTTP (communication channels), DISCO (used to create discovery documents) and UDDI (used to create business registries).

 32) Explain in brief, what DISCO is?

 DISCO means discovery. It groups the list of interrelated web services. The organization that provides web services, issues a DISCO file on its server and that file contains the links of all the provided web services. This standard is good when client knows the company already. Also it can be used within a local network as well.

 33) Explain in brief, what UDDI is?

 UDDI (Universal Description, Discovery, and Integration) provides consolidated directory for web services on the internet. Clients use UDDI to find web services as per their business needs. It basically hosts the web services from various companies. In order to share web services, you need to publish it in UDDI.

 34) Explain the .NET web services supported data types? 

 .Net web services uses XML-based standards to transfer/receive information. Thus, .NET web services can only works with data types known by XML schema standard. Like FileSteam, Eventlog etc. are not recognized by the XML schema standards and hence, not supported in web services.

 35) How a .NET web service is tested?

 ASP.NET uses a test page routinely, when one calls for the URL of .asmx file in any browser. This page shows complete information regarding web services.

 36) How a .NET web service is consumed?

 Since we know that web services are constructed on XML standards. Therefore, clients need to have complete understanding of XML-based messages to interchange messages. Clients can communicate with web services through .NET framework that offers proxy mechanisms. These proxy mechanisms have detailed information regarding data sharing within web services that can be easily used by the clients.

 37) Can you name the two Microsoft solutions for distributed applications?

 The two Microsoft solutions for distributed applications are .NET Web Services and .NET Remoting.

 38) Differentiate between .NET Web Services and .NET Remoting?

 As far as protocol is concerned, .NET Web Service uses HTTP, while, .NET Remoting uses any protocol i.e. TCP/HTTP/SMTP. When it comes to performance, .NET Remoting is comparatively, faster than.NET Web Service. Also, as .NET Web Services are hosted via IIS, therefore, it is far more reliable than the .NET Remoting.

 39) Name the components to be published while deploying a Web Service?

 The components that need to be published during a web service deployment are Web Application Directory, Webservice.asmx File, Webservice.Disco File, Web.Config File and Bin Directory.

 40) What are the steps performed by the client to access a web service?

 First of all a web reference to the web service is created by the client in his application. Then a proxy class is generated. After that an object of the proxy class is created and at last, the web service is accessed via that proxy object.

 41) How web services are implemented in .NET?

 To implement web services in .NET, HTTP handlers are used that interrupt requests to .asmx files.

 42) Explain few disadvantages of Response Caching?

 Response Caching is useless or incompetent when method accepts extensive amount of values because caching means to store lot of information.  Also, if the method depends on external source of information, and that are not provided within the parameters then such methods are bypassed.

 43) What is the alternate solution to Response Caching?

 One can use Data Caching (System.Web.Caching.Cach) instead of Response Caching.

 44) Brief few drawbacks of using GET and POST methods to communicate with the web service?

 These methods are less secure and inhibit users to pass structures and objects as arguments. Also, it doesn’t allow users to pass ByRef arguments.

 45) How can one access a class as a web service?

 To access a class as a web service, one should inherit the class from the System.Web.Services.WebService class and qualify the class with the WebService attribute.

 46) How can one access the web service class method via internet?

 To access web service class method via internet, one should qualify a method with the WebMethod attribute.

 47) How a SOAP message is structured?

 A SOAP message is consists of SOAP Envelope, SOAP Headers, and SOAP Body.

 48) Can you name different kinds of web services?

 There are two types of web services in total i.e. SOAP based web service and RESTful web service.

 This question is already mentioned earlier.

 49) What’s different in RESTful web services?

 The RESTful web services contains no contract or WSDL file.

 50) Give me few reasons to use RESTful web service?

 The RESTFul web services are simple to implement and test. It supports various data formats such as XML, JSON etc.

 51) Explain what is JAVA web services? What are the methods to create web services?

 Java webservices is developed to build and deploy basic web service on JAVA platform.

 To create a web services, there are two approaches that are adopted

 Top-down approach
Top-up approach
52) Explain what is JAXP?

 JAXP is a JAVA API for XML processing that enables application to write, read, manipulate and transform XML data.  Similarly, to perform other various function there are other Java API’s as well like JAX-RPC, JAXM, JAXR, JAXB, etc.

 53) Mention the JAXB binding framework?

 JAXB binding framework is available in three Java Packages

 xml.bind: This package defines abstract classes and interfaces that are used directly with content classes
xml.bind.util: This package contains utility classes that may be availed by client applications to manage marshalling, unmarshalling and validation events
xml.bind.helper: This helper package gives partial implementations for some of the javax.xml.bind interfaces. These APIs are not to be directly used by applications using JAXB architecture
54) Give a simple example of how XML document can be Marshal and Unmarshal in JAVA framework?

 Marshalling is the process of converting XML document into Java readable form while UnMarshalling is the reverse process of Marshalling.  Let see how Java unmarshals an XML document and then marshals it back

 JAXBContext jc= JAXBContext.newInstance (“com.acme.foo”);

 // unmarshal from foo.xml

 Unmarshaller u = jc.createUnmarshaller () ;

 FooObject fooObj=

 (FooObject)u.unmarshal (new File (“foo.xml”) );

 // marshal to sytem.out

 Marshaller m = jc.createMarshaller ();

 m.marshal (fooObj, System.out);

 55) Explain what does Marshaller do if jaxb.encoding property is not declared?

 By default, the Marshaller will use “UTF-8” if jaxb.encoding property is not declared.

 56) Mention what are the types of validation can a JAXB client can perform?

 There are two types of JAXB client validation that a JAXB can perform

 Unmarshal Time Validation
On-Demand Validation
57) Mention what are the three ways to handle the event encountered during the marshal, unmarshal and validate operations?

 Using the default event handler
Register and Implement a custom event handler
Use the ValidationEventCollector utility
58) Explain where does JAXB compiler is located?

 JAXB schema binding compiler is placed in the <JWSDP_Home>/jaxb/bin directory.  In this directory, there are two scripts, xjc.sh (Solaris/Linux) and xjc.bat (Windows).

 59) In what cases do you need to customize the default binding?

 In some cases, you are required to customize the default binding like

 Creating API documentation for the schema derived JAXB packages, classes, methods and constants
Giving semantically meaningful customized names for cases that the default XML name-to-Java identifier mapping cannot handle automatically
Overriding default binding- like specifying that a model group should be attached to a class rather than a list
60) Explain what is Inline Customization?

 Customization to JAXB bindings made by means of inline binding declarations  in an XML schema file that take the form of <xsd:appinfo> elements embedded in schema <xsd:annotation>elements.

 61) Explain what is XML signature?

 XML can be used to sign any arbitrary data whether it is a binary or XML.  The data is recognized via URIs in one or more reference elements.  It is described in one or more forms, like detached, enveloping or enveloped.

 62) Explain what is Stax?

 Stax stands for Streaming API for XML; it is an API to read and write XML documents, originating from the JAVA programming language.

 63) Mention what are the usual XML APIs?

 The usual XML APIs includes

 DOM based or Tree based APIs: The whole document is read into memory as a tree structure for random availability by calling application
Event based APIs: The application registers to get events as entities are encountered within the source document
64) Explain what is Push parsing and Pull parsing?

 Pull Parsing: Streaming pull parsing is referred to a programming model in which a client application calls methods on an XML parsing library, when it needed to communicate with an XML infoset- which means the client will only gets XML data when it is asked for
Push Parsing: In Push Parsing, the parser pushes parsing events or XML data to the application.  In push model, the parser got the hold over the parsing  process and the parser calls the implemented handler methods.
65) Explain on which technology does XWS security is based on? List out the options that XWS security provides for securing JAX-RPC applications?

 XWS security is based on securing web services build on JAX-RPC and on stand-alone application based on SAAJ.  For securing JAX-RPC application, options that XWS security provides are

 XML digital signature
XML encryption
Username token verification
XWS security framework APIs
66) List out the six packages available in XML Digital signature API?

 Digital signature API is

 xml.crypto
xml.crypto.dsig
xml.crypto.dsig.keyinfo
xml.crypto.dsig.spec
xml.crypto.dom
xml.crypto.dsig.dom
67) Explain what is JAXR?

 JAXR is the JAVA programming APIs for Java platform application to access and programmatically interact with various kinds of meta-data registries.

 68) Explain what does the JAXR architecture consist of?

 JAXR architecture is consists of a JAXR client and JAXR provider.

 JAXR client: It is a client program which uses the JAXR API to use a registry through a JAXR provider
JAXR provider: It is an implementation of the JAXR API that provide access to a particular registry provider or to a class of registry providers that are built on a common speicifications.
69) Explain what is JAXM messaging models?

 There are two types of messaging models for JAXM synchronous and asynchronous

 Synchronous messaging model: In such type of model, client directly communicates with the source. In this, the client will send the request and waits.
Asynchronous messaging model: In this model, client directs the message to the messaging provider and returns back.  Messaging provider then executes the routing of the message to the end source.
70) Explain what is UDDI, DISCO and WSDL?

 UDDI: It means Universal Description, Discovery and I It is the directory that is used to publish and discover public web services
DISCO: It is commonly known as discovery. It clubs common services together and exposes schemas document of the web services

WSDL: It stands for web service description language (WSDL). It is used to describe web services.  The description includes URL of web services, properties and methods supported by web services, data type it supports and protocol detail it supports

Posted by at No comments:
Subscribe to: Posts (Atom)