Mocha is a Java Decompiler and is 100% FREE to use.
The readme.txt file in the Mocha distribution offers the free usage license:
The distribution archive (file “mocha-b1.zip”) may be distributed freely, provided its contents (“mocha.zip” and this file, “readme.txt”) are not tampered with in any way.
I am pleased to be able to make the Mocha distribution available under those terms:
mocha-b1.zip (121K)
You can visit the alternative download location here.