Core Java Interview Questions and Answers

Core Java Interview Questions and Answers

50+ Core Java Interview Questions and Answers for beginners and experienced.

Today world’s one of the top most used programming language is Java. Java is a general purpose High Programming Language. Core java is the basic of java programming technology concept that term used by sun Microsystems to describe the standard version of java (JSE). Core Java is just a part of Java which stands for J2SE containing all the basics of Java including some principles and package details. The Core Java concept covers all OOPS Concepts, Special Operators, Data types, Wrapper Classes ,exception Handling, Polymorphism ,Multi-threading, Linked List, Queue, Stack ,Array List. It is most used for development of desktop applications and server environments (Develop standalone applications).

What is the difference between a JDK and a JVM?

What are the principle concepts of OOPS?

Can you explain Polymorphism?

What is the difference between an Inner Class and a Sub-Class?

What are the various access specifiers for Java classes?

Can you explain Static methods and static variables?

Is java support operator overloading?

Can overloaded methods be override too?

What is a data encapsulation and what’s its significance?

What is a singleton class? Give a practical example of its usage

What is a daemon thread?

What are Loops in Java? What are three types of loops?

Can you define deadlock?

What is an infinite Loop? How infinite loop is declared?

What is the difference between continue and break statement?

What is the difference between double and float variables in Java?

What is javac ?

What is Final Keyword in Java? Give an example

What is ternary operator?

What are 6 different types of operators in Java?

What is default switch case?

What’s the base class in Java from which all classes are derived?

Can main() method in Java can return any data?

What are Java Packages? What’s the significance of packages?

Can we declare a class as Abstract without having any abstract method?

What is difference between Heap memory and Stack Memory?

What’s the difference between an Abstract Class and Interface in Java?

What are the performance implications of Interfaces over abstract classes?

Does Importing a package imports its sub-packages as well in Java?

Can we declare the main method of our class as private?

How can we pass argument to a function by reference instead of pass by value?

How an object is serialized in java?

When we should use serialization?

Is it compulsory for a Try Block to be followed by a Catch Block in Java for Exception handling?

Is there any way to skip finally block of exception even if some exception occurs in the exception block?

When the constructor of a class is invoked?

Can a class have multiple constructors?

What does super keyword do?

Can we override static methods of a class?

Is String a data type in java?