How to access Environment Variables in an ANT build script

Often you tend to require to write an ANT build script with references to Environment Variables like 'JBOSS_HOME' or 'JAVA_HOME'.

This can be achieved using the following:
<property environment="env"/>
<property name="JBOSS_HOME" value="${env.JBOSS_HOME}"/>
<property name="JAVA_HOME" value="${env.JAVA_HOME}"/>