Runtime gc() in Java

Runtime.gc():

• Runtime class has non static gc() method.
• It is used to start garbage collector on request.
• Runtime object representing JVM directly.
• We request the JVM directly to start Garbage collector.

/*
class Runtime
{
	public void gc()
	{
		Runs the garbage collector. 
	}
}
*/
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<=10 ; i++)
		{
			new Test();
			Runtime jvm = Runtime.getRuntime();
			jvm.gc();
			try{
				Thread.sleep(1000);
			}catch(Exception e){ }
		}
	}
}

exec(String command):

• Pre-defined method belongs to Runtime class.
• It is used to execute a System command.
• JVM is also working like Virtual OS. Hence it can run OS commands as well.

class JVM
{
	public static void main(String[] args) throws Exception
	{
		Runtime jvm = Runtime.getRuntime();
		jvm.exec("notepad");
		jvm.exec("mspaint");
	}
}