148 interview questions on Java for developers (2025)

24 votes2605 runs

Pierreat Sep 19, 2022

16 votes3175 runs0 comment

control flow

Thomas De verdièreat Dec 16, 2021

13 votes1210 runs

12 votes3128 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3166 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

11 votes3091 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3028 runs0 comment

Thomas De verdièreat Dec 16, 2021

10 votes3222 runs0 comment

Thomas De verdièreat Jan 4, 2022

10 votes3089 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

10 votes2519 runs

Pierreat Sep 19, 2022

10 votes2439 runs

concatenation

Pierreat Jan 4, 2022

9 votes3030 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3162 runs

serialization

Thomas De verdièreat Dec 2, 2021

8 votes3158 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3061 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes2437 runs0 comment

Pierreat Jan 4, 2022

7 votes3149 runs0 comment

Thomas De verdièreat Dec 16, 2021

7 votes3048 runs1 comment

Thomas De verdièreat Jan 4, 2022

7 votes3035 runs0 comment

design patterns

Thomas De verdièreat Jan 4, 2022

7 votes2477 runs0 comment

Pierreat Sep 19, 2022

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; } ```

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

A monitor 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?

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?

How should a package be named 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 is the error message when you try to serialize a class that does not implement Serializable?

A “synchronized” method

What is the classpath for?

Add elements to an ArrayList in Java

Write a finalizer in Java.

What is the superclass of Integer, Long, Byte, BigDecimal and Short in Java?

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

Are arrays primitives types in Java?