UISpec4J

• API designed for readability: APIs are designed to make the test scripts as close as possible to human-readable text. (indented ASCII for checking the hierarchical contents of a Tree, two-dimensional arrays for checking the contents of a Table, etc.).
• Smart component search: the framework makes it possible to find UI components without requiring that the developers assign names to all of them. 
• Rely on displayed information only: the library checks the labels displayed by components instead of the string representation of their internal model data. To achieve this, the UI components check the values shown by the Swing component renderers.
• Invisible execution: the framework does not require that the GUI be visible when the tests are being run.
• No modifications needed in production code - no need to ship UISpec4J's JAR with deliverable product, and GUI tests can be written without needing to adapt your application design.
• Extensibility: ability to add own custom UISpec4J components to the library

• Smart color specification: colors are specified either with a string representation (in hexadecimal format, as in HTML), or with a human-readable name which is an approximation of the color - for instance, AA1100 is still "red".

Limitations

• Provides support for Swing components, and not older AWT ones
• Cannot test icons, mostly because there is no simple way to test icons for equality
• Cannot test focus management - the focus system does not seem to work when the components are not displayed.
• No specific support for Java2D
• No support for pure headless modes - even though UISpec4J tests run without displaying the GUI, we still need a valid graphics toolkit available on the computer.