Performance of Java exceptions

Influence of exception on the application performance
The first converter uses exceptions to determine if a value is not a Long value.

{% highlight java }
try {
value = Long.parseLong(toParse.trim());
} catch (NumberFormatException e) {
isLong = false;
}
{ endhighlight %}

The second example evaluates if the String contains of digits only.

{% highlight java %}
char buf[] = toParse.trim().toCharArray();

for (char c : buf) { if (!Character.isDigit©) isLong = false; } if (isLong) { value = Long.parseLong(toParse); }

{% endhighlight %}

With a String of “123456a” the second approach is more than 10 times faster. A shorter parse string requires even less time.

It is important to know that the time needed per thousand runs is only 2 milliseconds for the exception version. In most cases this should play no importance.

Kind Regards / Viele Grüße

Sebastian Hennebrueder