Set the ANT_HOME environment variable to the directory where you installed Ant. On some operating systems, Ant’s startup scripts can guess ANT_HOME (Unix dialects and Windows NT/2000), but it is better to not rely on this behavior.
Optionally, set the JAVA_HOME environment variable (see the Advanced section below). This should be set to the directory where your JDK is installed.
The ant.bat script makes use of three environment variables – ANT_HOME, CLASSPATH and JAVA_HOME. Ensure that ANT_HOME and JAVA_HOME variables are set, and that they do not have quotes (either ‘ or ") and they do not end with \ or with /. CLASSPATH should be unset or empty.