jstat is a jdk tool which is used to query the various quantities associated with the running JVM.

Java uses a garbage collector, which is the entity responsible for traversing the heap and freeing space that is being taken up by unreferenced objects.

In the Java runtime environment, there are two types of collections that can occur. The first type of collection is referred to as minor collection. Minor collections are responsible for locating live objects in the young generation (eden), copying these objects to the inactive survivor space, and moving tenured objects from the active survivor space to the old (tenured) generation (this assumes that a generational collector is being used).[1]

maximum heap capacity; ((OU+EU+S0U+S1U)/(OC+EC+S0C+S1C)) * 100