148 interview questions on Java for developers (2025)

25 votes2441 runs

Pierreat Sep 19, 2022

14 votes3035 runs0 comment

control flow

Thomas De verdièreat Dec 16, 2021

11 votes2998 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes1037 runs

10 votes3031 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

10 votes2988 runs0 comment

Thomas De verdièreat Jan 4, 2022

10 votes2918 runs0 comment

Thomas De verdièreat Dec 16, 2021

10 votes2292 runs

concatenation

Pierreat Jan 4, 2022

9 votes3113 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes2960 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

9 votes2927 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes2367 runs

Pierreat Sep 19, 2022

8 votes2960 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes2282 runs0 comment

Pierreat Jan 4, 2022

7 votes3040 runs0 comment

Thomas De verdièreat Jan 4, 2022

7 votes3018 runs0 comment

Thomas De verdièreat Dec 16, 2021

7 votes2974 runs1 comment

Thomas De verdièreat Jan 4, 2022

7 votes2916 runs0 comment

design patterns

Thomas De verdièreat Jan 4, 2022

7 votes2322 runs0 comment

Pierreat Sep 19, 2022

6 votes3043 runs0 comment

serialization

Thomas De verdièreat Dec 2, 2021

148 interview questions on Javafor developers (2025)

Test your technical skills before an interview of Java with 148 corrected questions. Beginner, Intermediate or Expert level.

148 interview questions on Javafor developers (2025)

Test your technical skills before an interview of Java with 148 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; } ```

A monitor in Java

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

Serialization can be customized with the Externalizable interface

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

How many instance of Integer cannot be freed from memory?

How to concatenate two strings of characters in Java?

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

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

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

How should a package be named in Java?

What is the classpath for?

Add elements to an ArrayList in Java

A “synchronized” method

Write a finalizer in Java.

What package contains the HashMap class in Java?

What design pattern will you use to dynamically add capabilities to an object in Java?

Are arrays primitives types in Java?

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