159 interview questions on Java for developers (2026)

38 votes3291 runs

Pierreat Sep 19, 2022

17 votes3636 runs

control flow

Thomas De verdièreat Dec 16, 2021

17 votes3186 runs

Pierreat Sep 19, 2022

15 votes1936 runs

14 votes3649 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

14 votes3582 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3535 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3474 runs0 comment

Thomas De verdièreat Dec 16, 2021

12 votes3672 runs0 comment

Thomas De verdièreat Jan 4, 2022

12 votes3631 runs

serialization

Thomas De verdièreat Dec 2, 2021

11 votes3629 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3524 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

11 votes3032 runs

concatenation

Pierreat Jan 4, 2022

10 votes3088 runs0 comment

Pierreat Jan 4, 2022

9 votes3442 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3420 runs2 comments

Thomas De verdièreat Jan 4, 2022

9 votes3109 runs0 comment

Pierreat Sep 19, 2022

8 votes3613 runs0 comment

Thomas De verdièreat Dec 16, 2021

8 votes3482 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3428 runs0 comment

Thomas De verdièreat Jan 4, 2022

159 interview questions on Javafor developers (2026)

Test your technical skills before an interview of Java with 159 corrected questions. Beginner, Intermediate or Expert level.

159 interview questions on Javafor developers (2026)

Test your technical skills before an interview of Java with 159 corrected questions. Beginner, Intermediate or Expert level.

Write a Java program that prints 'welovedev'.

How many times is the condition `(a++ < 15)` evaluated in the following code? ```java int a = 3; while (a++ < 15) { if ((a++ % 5) == 0) break; } ```

How should a package be named in Java?

What is the difference between an interface and an abstract class in Java?

Serialization can be customized with the Externalizable interface

A monitor in Java

What does the final keyword mean in front of a method in Java?

How many instance of Integer cannot be freed from memory?

A Customer class has the com.company.model package.

What is the error message when you try to serialize a class that does not implement Serializable?

A “synchronized” method

What "design pattern" makes it possible to offer a means of treating the elements of a tree without worrying about the course?

How to concatenate two strings of characters in Java?

Add elements to an ArrayList in Java

Which of these classes is the most suitable for composing a character string from several elements concatenated to each other?

What does the following code show?

Are arrays primitives types in Java?

Write a finalizer in Java.

What is the classpath for?

Java 5: where to place the "@Override" tag and why?