Because helps a friend to install and debug a Dongdong to use Javacc, try to use it. 1. Installation of JavaCC2.1: (This assumes that you have installed the Java2 JDK 1.4 or updated version.) Javacc2.1 is available in a .class file, download and execute the following commands C: /> Java $ Javacc_dir / javacc_1 ($ JAVACC_DIR refers to the directory of Javacc in your system) a moment, the system will pop up the GUI installation interface, which will of course be very simple. 2, JAVACC3.2 installation: Haha, this is simpler, just need to compress the ZIP. Official documents had this to say: Depending on which you downloaded, you should go to the directory where the file was installed and type something like: unzip javacc-3.0.zip or gunzip javacc-3.0.tar.gz tar xvf javacc-3.0 .tar That completion your installation.