Archive for the 'Java' Category

Passing JVM options to Maven

Wednesday, June 30th, 2010

If you are using maven to build your projects , then you might have found an out of memory condition in your tests.  Well, setting the MAVEN_OPTS variable with JVM specific options will help with this.

Example:

MAVEN_OPTS=-Xmx1024

Depending on what environment you are in, you will need to set this variable.

This will give the JVM more 1024 megs to work with and you can customize the number to fit your needs.

Java formatting a number with leading zeroes

Friday, July 17th, 2009

Recently, I had a Java project that needed to encode a set of numbers and I needed a fixed number of digits used for each number. I found the DecimalFormat class a good solution for my needs.

Here is a snippet of code to show a simple way to format a number with a fixed number of digits.

import java.text.DecimalFormat;

class TestEncoder
{
        public static void main(String[] args)
        {
                // This program expects one integer
                // argument and places it in the num1
                // variable. This program is not very
                // robust as to watch for no arguments
                // or to check if the argument is not
                // an integer.
                String num1 = args[0];
                String output;

                // This creates the Decimal Format instance
                // and assigns the formatting that we want
                // to use, in this case three characters .
                DecimalFormat dfmt =
                             new DecimalFormat("000");

                // This does the work of formatting the number
                // passed in on the command line to be at least
                // three digits.
                output = dfmt.format(new Integer(num1));

                // This just displays the results of the
                // dfmt.format(new Integer(num1)) command.
                System.out.println("Output: " + output);
}
}

The Decimal format allows for many more formatting options for numbers.

Make sure to look a the API docs for the version of Java that you are using:

http://java.sun.com/j2se/1.5.0/docs/api/java/text/DecimalFormat.html

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