The Load Testing Tools Directory lists open source and commercial software tools for load testing and performance testing with review and resources. https://www.loadtestingtools.org/
Most developers think that the most beneficial part of using test-driven development (TDD) are the tests. But, when done right, TDD improves the overall design of your code. This installment in the Evolutionary architecture and emergent design series walks through an extended example showing how design can emerge from the concerns that float up from testing. Testing is only a side effect of TDD; the important part is how it changes your code for the better.
Apache JMeter is open source Java desktop software designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions.
This post presents good practice for efficient UI test automation.
This video demonstrates the basic of Test Driven Development in Java using Eclipse. From basic tests and basic production code, to refactoring, and some splashes of Behavior Driven Development, watch production code get created test first.
The article “Writing Testable Code” presents practices to write more testable code with many examples in java, going a step further than just TDD.