OpenJDK is an open-source implementation of the Java Platform, Standard Edition, commonly used for running Java applications. OpenJDK includes the Java Runtime Environment (JRE) and the Java Development Kit (JDK) for developing and running Java programs. It is compatible with most Java applications and widely used in server environments. Debian 11 provides support for various versions of OpenJDK, including JDK 8, 11, and newer releases. It’s a robust and reliable choice for developers and system administrators working with Java.