Garbage collector

JVM does not require the programmer to manually allocate and release blocks of memory when creating or disposing of objects. The programmer can generally concentrate on just creating objects when he or she needs them.

A process known as the GC halts the application at certain intervals and scans the memory for objects that are no longer in scope (not reachable by any other object loaded at that point). It will remove those objects that can safely be deleted from the memory and reclaim the freed space.

This process used to cause very serious performance issues in the past, but the algorithm has improved much over the years. Also, if an application needs it, system administrators can configure many parameters of the GC to better control it.

The developer should always keep the high-level concept of the GC algorithm in mind. If you keep creating tons of objects and always keep them in the scope (meaning making it in such a way that all those objects can be reached, for example, by storing them in a list that the application can access), then out of the memory, errors are very likely to occur sooner or later.