Silk4J is an automated testing tool that supports test-driven development. It allows developers to write automated tests in Java prior to or alongside application development. Silk4J has features like a recorder for quickly creating tests and built-in synchronization that eliminates the need for manual waits. It also supports unattended testing and restoring the application if errors occur. Silk4J is designed to work with technologies like AJAX, Flex, and .NET and supports cross-browser testing without modifying scripts.