Sometimes an object will need to perform some action when it is destroyed. For example, if an object is holding some non-java resource such as a file handle or window character font, then you might want to make sure these resources are freed before an object is destroyed. To handle such situations, Java provides a mechanism called finalization. By using finalization, you can define specific actions that will occur when an object is just about to be reclaimed by the garbage collector.

A high value for this measure indicates the existence of many objects that are still occupying the JVM memory space and are unable to be reclaimed by GC. A consistent rise in this value is also a sign of a memory leak.