How is automatic memory cleanup performed in the runtime environment?

Automatic memory cleanup in the runtime environment, such as in Android, is performed using a garbage collector (Garbage Collector, GC). It monitors objects in memory and frees those that are no longer referenced in the program. This helps prevent memory leaks and releases resources without explicit developer intervention.

Working principle:

• The garbage collector runs periodically and scans the heap for objects that are unreachable from root references.
• Such objects are considered garbage, and their memory is freed.

In Android, Dalvik or ART runtime is used, which have their own GC implementations optimized for mobile devices.

Example in Java (Android):

// Create an object
MyObject obj = new MyObject();
// After obj is no longer used and references to it disappear,
// the garbage collector will automatically free the memory.
obj = null;
// System.gc() can be called to suggest GC, but it does not guarantee immediate cleanup.
System.gc();