1.How HashMap works?
2.When to override hashcode() and equals().
3.How to make an object immutable?
4.Difference between creating String new() and literal
5.Difference between abstract class and interface.
6.Difference between abstraction and encapsulation.
7.why wait() notify and notifyall() are in object class?
8.transient and volatile keywords.
9.Difference between iterator and lisiterator.(Class and interface hierarchy)
10.Deep copy and shallow copy.
11.sleep() and wait() difference.
13.Garbage collection. how to call it? does it always work?
14.Collection Hierarchy and exception class hierarchy.
15.Why collection doesnt extend serializable and cloneable?(What are marker interfaces?)
16.Why map doesnt extend collection interface?
17.Difference between collections questions.
18.How hashset works?
19.how many Null element added in hashset and treeset.
20.Difference between implements runnable and extend thread.
21.join() and yield()
22.Writing a deadlock and resolving.
23.producer and consumer problem.
24.overriding of methods like main(),static, abstract. Overriding and overloading rules.
25.how string pool works?memory management.intern().
26.widening and narrowing in inheritance and exception classes.
27.can we override wait() or notify() methods?
28.Heapoutofmemory : reasons, fixings, best practices
29. Singleton class. singleton in multithreaded
30.executors thread pool concepts.
31.Dynamic dispatch(static binding and dynamic binding)
32.Java passby value or reference – for java script?
0.1+0.2=? Why BigDecimal, Float etc IEEE7
33.”Semapore vs Lock, which controls the thread? OS?
34.What type of mechanism followed Preemptieve. How the contect swithing happens?”
35.Spring MVC – how do you control DOS attack? Header
36.jquery – how to apply style for all paragraphs
37.single java script minimized or multiple?
38.wht stack flow error?
39.What Ioc? Why Proxy used?