Abbot
Abbot helps you test your Java UI. It comprises Abbot, which lets you programmatically drive UI components, and Costello (built on Abbot) which allows you to easily launch, explore and control an application. The framework may be used with both scripts and compiled code.

Cactus
Cactus is a simple test framework for unit testing server-side java code (Servlets, EJBs, Tag Libs, Filters, ...). The intent of Cactus is to lower the cost of writing tests for server-side code. It uses JUnit and extends it. Cactus implements an in-container strategy, meaning that tests are executed inside the container.

dbMonster
dbMonster is a tool which helps database application developers with tuning the structure of the database, tuning the usage of indexes, and testing the application performance under heavy database load. dbMonster generates as much random test data as you wish and puts it into SQL database. It provides a very pluggable interface and is trivial to use. dbMonster is written in Java.

DbUnit
DbUnit is a JUnit extension (also usable with Ant) targeted for database-driven projects that, among other things, puts your database into a known state between test runs. This is an excellent way to avoid the myriad of problems that can occur when one test case corrupts the database and causes subsequent tests to fail or exacerbate the damage.

EasyMock
EasyMock provides Mock Objects for interfaces in JUnit tests by generating them on the fly using Java's proxy mechanism. Due to EasyMock's unique style of recording expectations, most refactorings will not affect the Mock Objects. So EasyMock is a perfect fit for Test-Driven Development.

Grinder
The Grinder is a JavaTM load-testing framework. It is freely available under a BSD-style open-source license.

Jamelon
Jameleon is an acceptance-level automated testing tool that separates applications into features and allows those features to be tied together independently, creating test-cases. These test-cases can then be data-driven and executed against different environments. Even though it would be possible to write unit tests using Jameleon, Jameleon was designed with integration and acceptance-level testing in mind.

jfcUnit
jfcUnit is an extension to the popular testing framework JUnit. This document assumes you are familiar with the usage of JUnit. If not, visit the main JUnit website where there are a number of links to some excellent resources on the subject.

jMock
jMock is a library for testing Java code using mock objects1. Mock objects help you design and test the interactions between the objects in your programs. The jMock package: makes it quick and easy to define mock objects, so you don't break the rhythm of programming; lets you define flexible constraints over object interactions, reducing the brittleness of your tests;
is easy to extend.

JTestCase
JUnit test framework provides an excellent way to formalize your test code. But due to its "none-input-param, none-return" design, generally you need to hard-code all test data for each testing method. And for each test cases of one unit test, you need to change test code, recompile it, and run it.