Make yield call optional

cm/Main.java

@@ -1,8 +1,8 @@
 public class Main {
 	public static void main (String argv[]) {
 		Thread t1, t2;
-		t1 = new DispTask();
-		t2 = new DispTask();
+		t1 = new DispTask(false);
+		t2 = new DispTask(false);
 
 		t1.start();
 		t2.start();

cm/Task.java

@@ -1,8 +1,16 @@
 class DispTask extends Thread {
+	boolean doYield;
+
+	DispTask(boolean _doYield) {
+		doYield = _doYield;
+	}
+
 	public void run() {
 		for (int i = 0; i < 10; i++) {
 			System.out.println(i);
-			// yield();
+
+			if (doYield)
+				yield();
 		}
 	}
 }