Useful constants that the Java compiler will in-line. A collection of reference interfaces that contain primitive or String constants. Such constants will be in-lined by the Java compiler hopefully leading to smaller footprint, than a reference to a field entails. Fields in interfaces are automatically public, static and final, hence constants.

These classes should not need to be shipped with any of the Derby jar files. If one is shipped with a Jar file then it most likely means the field representing the constant was a non-String Object (e.g. new Integer(1)) or the final field is a calculated value that could not be resolved to a constant by the Java compiler.