When you install JReport Designer, which by default is located in C:\JReport\Designer, the Catalog API is also installed at the same time. After installation, you will have the following components in <install_root>\lib:
The Catalog API class is stored in the archive file report.jar. You will need to do the two steps below before you can compile and run the program:
<install_root>\lib\report.jar;<install_root>\lib\sac.jar;<install_root>\lib\JREngine.jar;<install_root>\lib\log4j-1.2.8.jar