FULL PRODUCT VERSION :
ava version "1.7.0_65"
OpenJDK Runtime Environment (IcedTea 2.5.1) (7u65-2.5.1-5~deb7u1)
OpenJDK 64-Bit Server VM (build 24.65-b04, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Linux 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u3 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
InetAddress.getByName() invokes the internal method IPAddressUtil.textToNumericFormatV4(), which uses exceptions as a control structure. Several places in this method attempt to parse strings to integers, but these strings may or may not be numbers actually, so when they are not numbers, a NumberFormatException will be thrown and it will be caught by a catch{} clause that returns null.

This is a performance nug, because this exception is being thrown too frequently in my app (a real-time bidder that handles 20,000 requests/second; every single of these requests requires at least one of these InetAddress.getByName() calls, there's only a small number of addresses but this happens in a third-party embedded library that I cannot optimize e.g. with a simple cache. Processing of each request is relatively fast so this exception is wasting ~5% of all CPU consumed by my application (after discounting the epoll network layer).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Execute test code below.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Address resolved but without burning CPU :)
ACTUAL -
Address is correctly resolved, but wasting enough CPU to appear near the top of my performance profile.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.net.InetAddress;
import java.net.UnknownHostException;

public class InetAddressTester {
  public static void main(String[] args) throws UnknownHostException {
    System.out.println(InetAddress.getByName("::ffff:10.86.252.234"));
  }
}

---------- END SOURCE ----------