Current milliseconds, from long to int

Question

I currently have the following code:

public static int currentTimeMillis()
{
    long millisLong = System.currentTimeMillis();
    while ( millisLong > Integer.MAX_VALUE )
    {
        millisLong -= Integer.MAX_VALUE;
    }
    return (int)millisLong;
}

which returns the current time in an int format (not exactly, but it can be used for time differences). For very good reasons, I can't use long.

Yes, I am just interested in the difference between two calls, and this approach works well. But it just looks wrong. I know that. And inefficient. I know. So my questions is, how can I improve it?

I need a function that returns an int such that:

int x1 = currentTimeMillis(); //my function
long y1 = System.currentTimeMillis();

.....

int x2 = currentTimeMillis();
long y2 = System.currentTimeMillis();

// here, x2 - x1 must be equal to y2 - y1

EDIT:

FYI, I want to do this for benchmarking. I'm running tests on multiple threads in parallel, the stop event is triggered by an external component. I'm also serializing the data in a way that only supports int, and the object I'm serializing can not have long members.

Answer 1

Instead of finding a modulus, a much faster solution would be a simple bitwise mask operation:

public static int currentTimeMillis() {
    return (int) (System.currentTimeMillis() & 0x00000000FFFFFFFFL);
}