Collection Framework

• How to work HashMap Internally? Answer,,

• Type of to Map Implementation? Answer

• In java 8 what is TREEIFY_THRESHOLD and UNTREEIFY_THRESHOLD ? Answer

• How to work HashSet Internally? Answer,

• What is different between HasMap and ConcurrentHashMap? Answer,

• What is different between Hashmap between WeakHashMap in Java ? Answer,

• What is different Collection and Collections? Answer,

• what is different between ArrayList and LinkList ? Answer,

• what is different between ArrayList and Vector? Answer,

• what are the way retrieve data from collection ?

• what is different between iterator and enumerator ?

• What is Fail Safe & Fail-fast iterator ? Answer,

• Wt is diff between Iterator and ListIterator ?

• Wt is diff between comparable and comprator ? Answer, old answer

MultiTheading & Concurrency

• what thread and runnable ?

• what is callable ?

• what is executor framework? Answer, Type of

• what is diff between runable and callable ? Answer,

• what is future and lock ? Answer,

• what is synchronization ?

• what is diff between static synchronization and non static synchronization? or wt is diff between class level lock and object level lock ?

• what is consumer and producer problem ? Answer,

• what is exchanger? Answer,

• what is semaphore? Answer,

• what is circular barrier? Answer,

• what is countdown latch? Answer,

• What is diff between Excutor.submit() and Excutor.excute() ?

• Wt is dead lock? How can avoid deadlock in java ? Answer,

• wt is phaser ? Answer,

• wt is Fork/join ? Answer,

• Wt is Atomic operator ? answer

• Which design pattern is used Consumer Producer or Observer design Pattern? Answer,

• Explain how can implement company stack change then all client notify and which design patten used? Answer

• Wt is diff between transient and volatile keyword ? answer

Exception Handling

• what is Exception Handling ? Answer,

• what is different between checked exception and unchecked exception ? Answer,

• how can create custom exception ? Answer,

• How can overriding in Exception Handling ? answer

Oops

• what is polymorphic ? Answer,

• what is dynamic binding ?

• What is abstraction ? Answer,

• What is different between Interface and Abstract class ? Answer,

• what is serialization and deserialization ? Answer,

• During serialization and deserialization how can restrict some property ? Answer go to question 4,

• During serialization and deserialization suppose after some day adding another property then how can serialization and deserialization?Answer go to question 9,

• What is overloading and overriding ?

• What is hashCode() and equal() ?

• What is singlton ? Is singlton thread safe ? Answer

• Explain final, finally and finalize ? Answer,

• What is name less construtor and static block ?

• Wt Life cycle of thread ?

• Wt is diff between wait() and sleep() ?

• wt is clone? Diff between Deep cloning and shallow cloning? Answer,

String

• How can create immutable class ? Answer,

• what is literal? Answer,

• what is diff between equal() and == ? Answer,

• what is diff between object creation new String() and String s=""? Answer,

• What is diff between StringBuffer and StringBuilder ? Answer,

• Wt is String pool ?

• Wt is immutable class?Answer

java8 (functional programming)

• Java8 new feature

• What is Labda Expression ?

• What is java stream api explain ?

• What is forEach loop ?

Memory Managments

• What is jvm memory managment like parm gen, heap, stack ? answer my answer Deeply Answer

• Heap memory exceeded. How can resolved? Answer

• Perm Gen vs Metaspace in java8 ? Answer

• What is garbage collector? How many type? Answer

• What is jvm monitoring tools? And explain jvisual VM.

• What is java memory leak problem? How can handle it Answer

InputStream/OutputStream

• Wt is inputstream? Answer

• Wt is Outstream? Answer

Xml Parsing

• Wt is Xml parsing? Answer

Batch Processing

• Wt is batch processing? Answer

Java 9

Wt is Java 9 Feature Answer

java 17

Wt is Java 17 Feature Answer