Rechenpower testen: Leibnitz-Formel ( KEINE FREIKEKSE ! )

public class LeibnitzPi
{
	public static void main(String[] agrs)
	{
		long start = System.currentTimeMillis();

		double pi = 1;


		for(int i = 1; i < 125000000; i++)
		{
			if(i % 2 == 0)
				pi += 1.0 / (1 + i * 2); 
			else
				pi -= 1.0 / (1 + i * 2); 
		}

		pi *= 4;

		if(pi == 3.141592645589324)
			System.out.println("Zeit: "+ (System.currentTimeMillis() - start));
	}
}

import java.util.ArrayList;


public class LeibnitzPi
{
	public static long time_all = 0;

	public static void main(String[] agrs)
	{
		long startet = System.currentTimeMillis();
		long needed = 0;

		ArrayList<LeibnitzPiThread> thread = new ArrayList<LeibnitzPiThread>();

		for(int i = 0; i < 50; i++)
		{
			System.out.println("Starte Thread "+ (i + 1) +"...");
			LeibnitzPiThread lpit = new LeibnitzPiThread(i + 1);
			lpit.start();
			thread.add(lpit);
		}

		System.out.println("Alle gestartet, bitte warte...");


		while(thread.size() >= 1)
		{
			for(int i = 0; i < thread.size(); i++)
			{
				LeibnitzPiThread th = thread.get(i);
				if(th.isAlive() == false)
					thread.remove(i);
			}
		}

		needed = System.currentTimeMillis() - startet;


		System.out.println("----------");
		System.out.println("Threads:\t\t50");
		System.out.println("Laufzeit:\t\t"+ needed +"ms");
		System.out.println("Laufzeit zusammen:\t"+ time_all +"ms");
		System.out.println("----------");

		System.exit(0);
	}
}

public class LeibnitzPiThread extends Thread implements Runnable
{
	private int mythread = 0;

	public LeibnitzPiThread(int threadid)
	{
		mythread = threadid;
	}

	public void run()
	{
		long start = System.currentTimeMillis();

		double pi = 1;
		for(int i = 1; i < 125000000; i++)
		{
			if(i % 2 == 0)
				pi += 1.0 / (1 + i * 2); 
			else
				pi -= 1.0 / (1 + i * 2); 
		}

		pi *= 4;

		long timeneeded = System.currentTimeMillis() - start;
		System.out.println("--- Thread: "+ mythread +"\nErgebniss: "+ pi +"\nZeit: "+ timeneeded +"\n");
		LeibnitzPi.time_all += timeneeded;
	}
}