60+ Coffee Interview Questions For Quick Revision

Java Interviews are real dissimilar than traditional software developer interviews. You tin clear a Java interview without fifty-fifty writing a unmarried describe of piece of job of code, Yes, this is true, you lot tin perish a Java developer without mortal scream for you lot to write a role inward Java interview. Though it's non the instance everywhere in addition to many companies are increasing including a coding assay inward their Java developer interview process, simply in that place are many companies in addition to start-ups where you lot tin teach a Java task without writing a unmarried describe of piece of job of code. All you lot demand to orbit is memorize those criterion Java questions, which has been asked from ages in addition to generally assay the theoretical noesis of the candidate. This is swell for candidates which lack hands-on coding experience, simply sometimes this trend of the interview tin terms you lot expert developers who are non expert at interviews. Someone, who knows how to construction a complex program, knows how to model their bird in addition to objects, tin write good, robust code simply neglect to respond questions like, Why String is Immutable? or How HashMap plant inward Java?


Since I own got gone through a lot of such interviews in addition to fifty-fifty conducted yoke of them, I idea to compile a listing of around of the most oft asked Java interview questions, roofing cardinal topics similar pattern patterns, pattern principles, OOP, JVM internals, Garbage collection, multithreading, generics in addition to collections, XML parsing in addition to others. This listing is collection fo such questions. I own got non answered them correct hither because I own got already answered them inward their private post service inward this blog, you lot tin see the respond link to run across the answer. 

Java Interview Questions for Freshers in addition to Experienced

1) What is Composite pattern pattern?

2) Explain Liskov exchange principle?

3) Write a Java programme to convert bytes to long?

4) What is faux sharing inward multithreading Java?

5) Can nosotros brand an array volatile inward Java? What is the number of making it volatile? (answer)

6) What is wages in addition to disadvantage of busy spin waiting strategy? (answer)

7) H5N1 deviation betwixt DOM in addition to SAX parser inward Java? (answer)

8) Write wait-notify code for producer-consumer problem? (solution)

9) Write code for thread-safe Singleton inward Java? (answer)

10) What are four ways to iterate over Map inward Java? Which ane is best in addition to why? (solution)

11) Write code to take elements from ArrayList spell iterating? (example)

12) is Swing thread-safe? (answer)

13) What is thread local variable inward Java? (answer)

14) How orbit you lot convert a String to engagement inward Java? (example)

15) Can nosotros usage String inward the switch case? (Yes)

16) What is constructor chaining inward Java? (answer)

17) Explain Java Heap infinite in addition to Garbage collection? (answer)

18) Difference between major in addition to nipper GC? (answer)

19) Difference between -Xmx in addition to -Xms JVM option? (answer)

20) How to banking concern fit if a String contains exclusively numeric digits? (regular expression)

21) Difference between poll() in addition to remove() method of Queue inward Java?

22) Difference between Comparator in addition to Comparable inward Java? (answer)

23) Why you lot demand to override hashCode, when you lot override equals inward Java? (answer)

24) How HashSet plant internally inward Java? (answer)

25) How orbit you lot impress Array inward Java? (answer)
26) Explain what 'path to root' way inward the context of garbage collection. What are roots?

27) Write code for a uncomplicated implementation of HashMap/Hashtable

28) Write a brusk programme to illustrate the concept of deadlock

29) Explain why recursive implementation of QuickSort volition require O(log n) of additional space

30) Explain the pattern pattern used inward Java in addition to .NET io stream/reader APIs.

31) Create an Iterator filtering framework: an IObjectTest interface amongst a unmarried boolean test(Object method in addition to an Iterator sub-class which is initialized amongst around other Iterator in addition to an IObjectTest instance. Your iterator volition hence allow iteration over the original, simply skipping whatever objects which don't transcend the test. Create a uncomplicated unit of measurement assay for this framework.

32) Difference betwixt Abstract bird in addition to Interface - given a province of affairs what would you lot conduct betwixt abstract bird in addition to interface? (answer)

33) Difference betwixt inheritance in addition to composition? (answer)

34) Difference betwixt ArrayList in addition to linked list? (answer)

35) Difference betwixt slumber in addition to wait? (answer)

36) Explain almost HashMap (methods inward HashMap in addition to  the projection inward which nosotros own got used the HashMap to a greater extent than almost equals() in addition to hashCode()  (answer)

37) Explain the methods inward Object class? (answer)

38) What is coupling? How orbit you lot cut down coupling in addition to why?

39) Struts config file - tin in that place last multiple configs? (answer)

40) Design patterns - factory, abstract factory, singleton implemented? (answer)

41) What does static, in conclusion mean, purposes; (answer)

42) How many accessibility modifiers exist? Please depict them. (answer)

43) Why orbit you lot demand a top dog method? (answer)

44) How many constructors tin you lot have?

45) Define overwriting in addition to overloading? (answer)

46) Give coffee API implementations for overwriting in addition to overloading

47) Describe the String bird – unique properties (answer)

48) StringBuilder vs StringBuffer? differences? (answer)

49) Collections: delight describe, give around examples in addition to compare them to each other

50) ArrayList vs Vector? Differences, when to usage which information structure? (answer)

51) HashMap vs Hashtable (answer)

52) What’s a tree inward Java? How dissimilar is from the tree inward information structure?

53) What’s a map? 

54) Multithreading: depict the thread management inward Java?

55) What’s a semaphore? (answer)

56) How many states are in that place for threads?

57) Describe the usage for synchronized discussion (2)? (examples)

58) Serialization inward coffee – a description in addition to usage? (example)

59) Garbage collection inward coffee – description in addition to usage

61) Can you lot guarantee the garbage collection process? No

62) Singleton, delight depict top dog features in addition to coding (answer)

63) Factory. delight depict top dog features in addition to coding (answer)

64) Have you lot used others? delight depict them?

What is the travel of this listing of  Java Interview questions?
The sole travel is to deport mock Java interviews past times yourself. You tin usage this listing to orbit in conclusion infinitesimal revision. Since answers are non provided, you lot tin endeavour answering them in addition to if you lot tin hence you lot are laid to accept on whatever telephonic circular of Java interview or face-to-face circular which doesn't involve coding.