159 interview questions on Java for developers (2026)

40 votes3370 runs

Pierreat Sep 19, 2022

17 votes3674 runs

control flow

Thomas De verdièreat Dec 16, 2021

17 votes3260 runs

Pierreat Sep 19, 2022

15 votes2016 runs

14 votes3686 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

14 votes3611 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3570 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3510 runs0 comment

Thomas De verdièreat Dec 16, 2021

13 votes3664 runs

serialization

Thomas De verdièreat Dec 2, 2021

12 votes3707 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3669 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3560 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

11 votes3157 runs0 comment

Pierreat Jan 4, 2022

11 votes3101 runs

concatenation

Pierreat Jan 4, 2022

9 votes3482 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3460 runs2 comments

Thomas De verdièreat Jan 4, 2022

9 votes3182 runs0 comment

Pierreat Sep 19, 2022

8 votes3654 runs0 comment

Thomas De verdièreat Dec 16, 2021

8 votes3520 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3461 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?

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

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

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?

Add elements to an ArrayList in Java

How to concatenate two strings of characters 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?