Java Garbage Collection
In java, garbage means unreferenced objects.
Garbage Collection is process of reclaiming the runtime unused memory automatically. In other words, it is a way to destroy the unused objects.
To do so, we were using free() function in C language and delete() in C++. But, in java it is performed automatically. So, java provides better memory management.
Advantage of Garbage Collection
How can an object be unreferenced?
There are many ways:
1) By nulling a reference:
2) By assigning a reference to another:
3) By anonymous object:
The finalize() method is invoked each time before the object is garbage collected. This method can be used to perform cleanup processing. This method is defined in Object class as:
Note: The Garbage collector of JVM collects only those objects that are created by new keyword. So if you have created any object without new, you can use finalize method to perform cleanup processing (destroying remaining objects).
The gc() method is used to invoke the garbage collector to perform cleanup processing. The gc() is found in System and Runtime classes.
Note: Garbage collection is performed by a daemon thread called Garbage Collector(GC). This thread calls the finalize() method before object is garbage collected.
Simple Example of garbage collection in javaTest it Now
object is garbage collected object is garbage collected
Note: Neither finalization nor garbage collection is guaranteed.