What is "retrotranslator"

Retrotranslator is a program written in Java that converts Java classes ( bytecode). The source classes may use Java 1.5 and Java 1.6 features, whereas the target will be compatible with Java 1.4 and older environments.

Retrotranslator supports all Java 5 language features and part of the Java 5 API on both J2SE 1.4 and J2SE 1.3. On older Java environments only the Java 5 features that don't depend on the new API are supported. Retrotranslator is based on the ASM bytecode manipulation framework and the backport of the Java 5.0 concurrency utilities (see http://backport-jsr166.sourceforge.net/ )

The Stripes Framework developers suggest to use Retrotranslator in order to use Stripes (which extensively use Java 1.5 features) on a Java 1.4 environment 1