Definition:

java-common: Base of all Java packages This package must be installed in the system if a Java environment is desired. It covers useful information for Java users in Debian GNU/Linux, including: - The Java policy document which describes the layout of Java support in Debian and how Java packages should behave. - The Debian-Java-FAQ which provides information on the status of Java support in Debian, available compilers, virtual machines, Java programs and libraries as well as on legal issues.

From Debian 3.0r0 APT

* Linux/Unix/Computing Glossary