Starting a process in a simple for-loop depending on the type of iterator (potential JVM bug?)

A very simple for-loop that I used as a dummy to keep my machine busy would block all my JVM processes. The collision persisted even in the simplest constellation.

Here is an example of two for-loops (the first one is blocking, the second one is not), the only difference is the type of iterator i, namely int vs. long:

public class Main {
public static void main(String[] args) {

    Timer timer = new Timer();
    timer.schedule(new MyTimerHandler(), new Date(), 1000);
    float b = 1;

    // after a few seconds this loop uses 200% CPU and blocks the timer 
    for (int i=0; i<2000000000; i++) {
        b += i/3.141592;
    }
    System.out.println("Result: " + b);
    b = 1;

    // this version uses 100% CPU throughout the entire loop and doesn't block the timer
    for (long i=0; i<2000000000L; i++) {
        b += i/3.141592;
    }
    System.out.println("Result: " + b);
    timer.cancel();
 }
}
// helps to show whether the JVM is stalled or not
class MyTimerHandler extends TimerTask {
    @Override
    public void run() {
        System.out.println("timestamp=" + new Date().toString());
    }
}

      

        
        
        
      

    

We have reproduced the problem on two different machines / jvms:

• Arch Linux 3.7.7-1-ARCH ... x86_64 GNU / Linux java version "1.7.0_09", Java (TM) SE Runtime Environment (build 1.7.0_09-b05)
• OSX 10.8.2 ... x86_64 java version "1.7.0_07", Java (TM) SE Runtime Environment (build 1.7.0_07-b10)

UPDATE and clarification:

• The question is WHY and WHAT EXACTLY is happening, not "allow" this example, but because the first for-loop behaves so strangely, using 2x more CPU and blocking all JVM threads.
• The sample code ends and gives the correct result.
• The timer is for demonstration only, problems occur with or without it.
• The int limit is over 2,000,000,000.
• The problem affects all tested JVMs so far.
• JProfiler and other debugging tools interrupted / stopped during first for-loop.