synchronized test

Main.java

public class Main {

	public static void main(String[] args) {
		MyThreadUnsafeTestObject o1 = new MyThreadUnsafeTestObject();
		MyThreadSafeTestObject o2 = new MyThreadSafeTestObject();
		long start = System.nanoTime();
		for (int i = 0; i < 1000000; i++) {
			o1.foo();
		}
		System.out.println("Unsynchronized calls took " + (System.nanoTime() - start) / 1E6D + " ms");
		start = System.nanoTime();
		for (int i = 0; i < 1000000; i++) {
			o2.foo();
		}
		System.out.println("Synchronized calls took " + (System.nanoTime() - start) / 1E6D + " ms.");
	}
	
	

}

class MyThreadUnsafeTestObject {
	public double d;
	public void foo() {
		double d = 4 * Math.sinh(3.1D) * Math.pow(20, 1.74D) * 1000;
		while (d > Math.PI) {
			d = d / Math.pow(d, Math.PI);
		}
		this.d = d;
		if (this.d != 1.5887418471800228E-15) {
			throw new RuntimeException();
		}
	}
	
}

class MyThreadSafeTestObject {
	public double d;
	public synchronized void foo() {
		double d = 4 * Math.sinh(3.1D) * Math.pow(20, 1.74D) * 1000;
		while (d > Math.PI) {
			d = d / Math.pow(d, Math.PI);
		}
		this.d = d;
		if (this.d != 1.5887418471800228E-15) {
			throw new RuntimeException();
		}
	}
}