Noughts

One of the most common examples used to illustrate exceptions is the “division by zero” example.
Exception in thread “main” java.lang.ArithmeticException: / by zero
I think I’ve seen it in a few Java books, so I’ve always had this impression that it’s never ok to divide a number by zero. Until I started preparing for the SCJP, that is. I ran the code below.

import java.io.*;
 
class TestDivideByZero
{
	public static void main(String[] arg) throws IOException
	{
		System.out.println(1/0.0);	//prints "Infinity"
		System.out.println(1.0/0);	//prints "Infinity"
		System.out.println(-1/0.0);	//prints "-Infinity"
		System.out.println(-1.0/0);	//prints "-Infinity"
		System.out.println(1/0);	//runtime error here
		System.out.println(-1/0);	//runtime error here
	}
}

So what’s up? According to Sun:

Despite the fact that overflow, underflow, division by zero, or loss of information may occur, evaluation of a floating-point division operator / never throws a run-time exception.

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This entry was posted on Tuesday, February 6th, 2007 at 10:35 pm and is filed under Java, J2EE. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.