JadRetro is a command-line utility that could help You to successfully decompile Java classes created by the modern Java compilers (of Java 1.4, Java 1.5 or later).
JadRetro operates by transforming the specified Java class files (if needed) into ones which could be processed correctly by an old Java decompiler (designed to work with classes of Java 1.3 or earlier).
JadRetro is not a decompiler itself, it is a class transformer helping some old (but good and time-proved) Java decompilers to convert more class files and/or generate more correct (legacy) source code.
JadRetro is tested and best works in conjunction with JAD (the Java Decompiler).