A memory leak may happen when an object can't be collected and can't be accessed by running code. The situation when memory that is no longer needed isn't released is referred to as a memory leak. In an environment with a GC, such as the JVM, a memory leak may happen when a reference to an object that's no longer needed is still stored in another object. This happens due to logical errors in program code, when an object holds a reference to another one when the last isn't used and isn't accessible in the program code anymore. The following diagram represents this case:
The GC cares about unreachable, also known as unreferenced, ...
