11 best Java Assertion libraries in 2025
by marketing.admin@openweaver.com 
Updated: Mar 12, 2023
Guide Kit
Java Assertion is a mechanism to indicate that the programmer thinks that something unexpected has happened. It is like a sanity check in a code and should be used to ensure that the code works as expected. Assertion statements are available since Java 1.4 and can be enabled or disabled as per requirement. Assertions should not be used for user input validation, the normal flow of program execution, or any exception handling. Java Assertion Libraries is one of the most popular open-source libraries for assertion in Java. These libraries are useful to check whether the actual result and expected result are equal or not. Let's take a look at some of the most popular and useful assertion open source libraries in 2022 truth - Fluent assertions for Java and Android; assertj-core - library providing easy to use rich typed assertions; ArchUnit - Java architecture test library.
assertj-coreby assertj
2134 Version:CurrentAssertJ is a library providing easy to use rich typed assertions
assertj-coreby assertj
Java 2134 Version:Current License: Permissive (Apache-2.0)
ArchUnitby TNG
2712 Version:v1.0.1A Java architecture test library, to specify and assert architecture rules in plain Java
ArchUnitby TNG
Java 2712 Version:v1.0.1 License: Permissive (Apache-2.0)
fest-assert-2.xby alexruiz
401 Version:CurrentFEST Fluent Assertions 2.x
fest-assert-2.xby alexruiz
Java 401 Version:Current License: Permissive (Apache-2.0)
livedata-testingby jraska
397 Version:1.3.0TestObserver to easily test LiveData and make assertions on them.
livedata-testingby jraska
Java 397 Version:1.3.0 License: Permissive (Apache-2.0)
jfrunitby moditect
225 Version:v1.0.0.Alpha2A JUnit extension for asserting JDK Flight Recorder events
jfrunitby moditect
Java 225 Version:v1.0.0.Alpha2 License: Permissive (Apache-2.0)
scottby dodie
125 Version:3.6.0Never debug a test again: Detailed failure reports and hassle free assertions for Java tests - Power Asserts for Java
scottby dodie
Java 125 Version:3.6.0 License: Permissive (MIT)
assertj-dbby assertj
97 Version:assertj-db-2.0.2Assertions for database
assertj-dbby assertj
Java 97 Version:assertj-db-2.0.2 License: Others (Non-SPDX)
jplusoneby adgadev
94 Version:CurrentTool for automatic detection and asserting "N+1 SELECT problem" occurences in JPA based Spring Boot Java applications and finding origin of JPA issued SQL statements in general
jplusoneby adgadev
Java 94 Version:Current License: Permissive (Apache-2.0)
assertj-swingby assertj
87 Version:3.17.1Fluent assertions for Swing apps
assertj-swingby assertj
Java 87 Version:3.17.1 License: Others (Non-SPDX)
kubernetes-assertionsby fabric8io
8 Version:v4.0.0This library provides a bunch of helpful assertj assertions for working with the kubernetes-api
kubernetes-assertionsby fabric8io
Java 8 Version:v4.0.0 License: Permissive (Apache-2.0)