Explain OOPS Concept? What is Polymorphism and Types of polymorphism? Write Code for compile time and Run time Polymorphism? What are singleton class and factory method? What is Exception and Exception Hierarchy? What are throwable Keywords and some question related to try and catch Syntax? What is Volatile Keyword? Difference between abstract class and interface? What is Functional Interface? What is Junit? Difference between Hashmap and ArrayList? Write code to remove element from Hashmap? Can overiding possible in same class? How many data structure you familier with? What is Binary Search?Write a program to implement Binary tree? How Many types of Collection are there? what is stack can you implement it. Write a program to convert element like this in an array Input [1,1,1,0,1] output [0,0,0,1,0] Write program of array input [3,6,8,9] output [1,2,4,5,7,10] Types of Thread Implementation in java? Write a program to reverse a string? Write a Program input Jay2 output JayJay

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Accepted Answer

Java interview questions on OOPS concepts, polymorphism, exceptions, data structures, and threading.

OOPS concepts include encapsulation, inheritance, and polymorphism.
Polymorphism refers to the ability of an object to take on multiple forms.
Singleton class is a class that can only have one instance, while factory method is a method that creates objects.
Exception is an error that occurs during program execution, with a hierarchy of exceptions.
Volatile keyword is used to indicate that a variable's value may be modified by multiple threads.
Abstract class is a class that cannot be instantiated, while interface is a collection of abstract methods.
Functional interface is an interface that has only one abstract method.
Junit is a testing framework for Java programs.
Hashmap and ArrayList are both data structures in Java, with Hashmap being a key-value pair and ArrayList being a dynamic array.
Binary search is a search algorithm that finds the position of a target value within a sorted array.
Thread implementation in Java includes extending the Thread class or implementing the Runnable interface.
Array programs include removing an element from a Hashmap, converting elements in an array, and reversing a string.
Jay2 can be converted to JayJay using string concatenation.

Accepted Answer

Oops concepts include encapsulation inheritance and polymersem

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