JMock
As a library, JMock supports the test-driven development of Java code with mock objects. These so-called mock objects allow developers to design and test interactions between the objects used in their programs
JUnit
JUnit functions as a unit testing framework for the Java programming language. It has been an integral part of the growth of test-driven development. JUnit is part of a family of unit testing frameworks that are known as xUnit as a whole. This framework collective originated with SUnit.
HTMLUnit
It is an open source library and a headless browser in Java which can be used for Java web testing. So, in it, java containers can be used for testing web applications. It is usually suitable for regression testing – the testing of whole application again after it has been changed.
TestNG
TestNG is a java testing framework, inspired by JUnit, which covers a wide variety of tests ranging from unit tests, functional tests, integration tests, etc. It is preferred in testing functionalities such as testing code in multi-thread environment and performing data-driven testing supports for dynamic data.
EasyMock
Released under the Apache License, EasyMock is an open-source testing framework that works for Java. It lets users create test double objects, making it useful for test-driven and behavior-driven development.
JWalk
JWalk is a testing tool that is famous for exhaustive testing of Java compiled classes. It is useful in cases where source code is not available so the compiled classes can be used. So, it can be used to retest the modified code and testing and validating the changes made so compliance is tested.
JMeter
Apache JMeter can be utilized as a load testing tool that analyzes and quantifies performance across various services, focusing primarily on web applications. This Apache project can also function as a unit-test tool for JDBC database connections, Webservices, FTP, LDAP, JMS, HTTP, OS native processes, and generic TCP connections.