Java interview questions

Most Common Java interview questions

Most Common Java interview questions

In this post, I’ll go through some of the most important Java interview questions and answers to help you stand out during the interview. Read the following article to find out all the information you need.

Java interview questions

We talk about Java interview questions because around 10 million developers use Java globally to create and develop apps for the 15 billion Java-enabled devices.

It is also utilized to develop cutting-edge technologies such as Big Data to be delivered to home devices such as mobile phones and DTH boxes.

As a result, Java is now utilizing worldwide!

This is why Java Certification is the most sought-after certification in the programming sector.

Basic Java Interview Questions

What is the significance of Java, a platform-independent language?

Because the compiler compiles the code and then transforms it to platform-independent byte code that can be executed on various systems.

The Java language does not rely on any hardware or software.

The sole need for running that byte code is that the system has a Java runtime environment (JRE) installed.

Why isn’t Java an entirely object-oriented language?

Because Java includes primitive data types such as:

  • Byte
  • Boolean
  • Char
  • Short
  • Int
  • Float
  • Long, and double

It is not strictly an object-oriented language.

In C/C++, pointers are utilized… Why is it that Java does not make use of information?

This Question is one important of Basic Java Interview Questions.

Beginner programmers should avoid using pointers since they are highly complex and dangerous.

Java emphasizes code simplicity, yet the use of references can make this difficult.

The usage of pointers might potentially lead to problems.

Furthermore, the usage of pointers compromises security since users can directly access memory with the help of tips.

By not including pointers in Java, a certain amount of abstraction is providing.

Pointers can also slow down the procedure of garbage collection or cause it to be inaccurate.

In Java, references are using because, unlike pointers, they cannot be modified.

Encapsulation of data: what do you mean by it?

  • Data Encapsulation is an Object-Oriented Programming technique that hides the data characteristics and actions in a single unit, a data unit.
  • Each object has its methods, properties, and capabilities.
  • As a result, it acts as a means of data concealment.

Read: 15 C# Interview Questions

What is a transitory variable, and what does it do?

The serialization procedure does not include transient variables.

The temporary variables’ values are set to the default value after deserialization.

It isn’t utilized with variables that aren’t static.

Basic Java Interview Questions: How does the JIT compiler work?

  • You may improve the performance of your application by using JIT (Just-In-Time).

As the name implies, it compiles at the same time portions of byte code that have comparable functionality.

  • Compiled source code is translated into machine-readable code by the compiler.

What makes the JIT compiler special? Let’s see what happens:

The javac compiler uses to convert Java source code (.java) to byte code (.class) for the first time.

The .class files are then loaded by JVM at runtime and translated to machine-readable code with the assistance of an interpreter.

JVM includes a JIT compiler

When the JIT compiler is enabled, the JVM analyses and compiles method calls .class files to produce more efficient and native code.

It also guarantees that the method calls that are prioritized are optimized.

After completing the preceding step, the JVM executes the optimized code directly rather than reinterpreting it.

This improves the execution’s efficiency and speed.

Describe how the final keyword is used in variables, methods, and classes

This is another point in Java interview questions.

The final keyword represents the non-access modifier in Java, which defines anything as constant conclusive.

The final variable is:

When a variable declares as final in Java, the variable’s value cannot be changed once it has been assigned.

If no value has been given to the variable, it can only be assigned by the class’s function.

The final method is:

Its children’s classes can’t override a final method.

A function cannot be declared final since constructors are not inherited when a class is inherited.

As a result, labeling it as final makes no sense.

Java throws a compilation error stating that the modifier final is not permitted in this context.

modifier final not allowed here

The last class is:

There are no classes that may be inherited from a final polish.

However, that final class may be used to extend other types.

Java interview questions: Is it possible to overload static methods?


In a class, two or more static methods with the same name.

But different input arguments might exist.

Is it possible to override static methods?

No, It isn’t.

In such circumstances, static methods with the same signature can be declared in the subclass, but runtime polymorphism is impossible.

During runtime, overriding or dynamic polymorphism happens.

Although static methods are loaded and looked up statically at build time.

As a result, these techniques are not overtaking.

What is the primary goal of waste collection?

The primary goal of this procedure is to free up memory space used by unneeded and inaccessible objects during the execution of a Java application by removing those objects.

This guarantees that the memory resource is using effectively.

But it does not guarantee that there will be enough memory available for the application to run.

In the garbage collection procedure, which component of memory is cleaned: the stack or the heap?

The answer to this critical Java interview question is Heap.


These are some of the most common JAVA interview questions, including fundamental and advanced Java concepts for programming and developer interviews, which our JAVA specialists have answered.

We hope that this lesson has provided you with a thorough understanding of JAVA’s basic coding principles.

The above explanations will significantly expand your knowledge and comprehension of JAVA programming.

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