Difference between system.gc() and runtime.gc()

Both are same. System.gc() is effectively equivalent to Runtime.gc(). System.gc()internally calls Runtime.gc().

The only difference is System.gc() is a class method where as Runtime.gc() is an instance method. So, System.gc() is more convenient.

From looking at the source code: System.gc() is implemented as

Runtime.getRuntime().gc();

So it's just a convenience method.

See the docs

System.gc() is equivalent to Runtime.getRuntime().gc()

Runtime.gc() is a native method where as System.gc() is non - native method which in turn calls the Runtime.gc()

System.gc():

1: It is a class method(static method).

2: Non-Native method.(Code which doesn't directly interacts with Hardware and System Resources).

3: System.gc(), Internally calls Runtime.getRuntime().gc().

Runtime.gc():

1: Instance method.

2: Native method(A programming language which directly interacts with Hardware and System Resources.).