Garbage Collection Program in Java

Overriding finalize method:

class Test
{
	Test()
	{
		System.out.println("Created : " + this);
	}
	protected void finalize()
	{
		System.out.println("Deleted : " + this);
	}
}
class GCDemo 
{
	public static void main(String[] args) 
	{
		new Test();
		new Test();
	}
}

• In the above application, we have created unreferenced objects.
• GC thread is not invoking finalize() method to delete those objects.
• GC thread invokes by JVM only when the memory is running low.
• GC thread will not execute continuously in the application.
• When JVM executes GC thread in the background continuously that will decrease application performance.

Creating thousands of unreferenced objects to check the execution of finalize() method:

class Test
{
	Test()
	{
		System.out.println("Created : " + this);
	}
	protected void finalize()
	{
		System.out.println("Deleted : " + this);
	}
}
class GCDemo 
{
	public static void main(String[] args) 
	{
		for (int i=1 ; i<=8000 ; i++)
		{
			new Test();
		}
	}
}

Note: increase the count of loop if you cannot see the execution of finalize method in your system.