Use Ant for running program with command line arguments

Extending Richard Cook's answer.

Here's the ant task to run any program (including, but not limited to Java programs):

<target name="run">
   <exec executable="name-of-executable">
      <arg value="${arg0}"/>
      <arg value="${arg1}"/>
   </exec>
</target>

Here's the task to run a Java program from a .jar file:

<target name="run-java">
   <java jar="path for jar">
      <arg value="${arg0}"/>
      <arg value="${arg1}"/>
   </java>
</target>

You can invoke either from the command line like this:

ant -Darg0=Hello -Darg1=World run

Make sure to use the -Darg syntax; if you ran this:

ant run arg0 arg1

then ant would try to run targets arg0 and arg1.

If you do not want to handle separate properties for each possible argument, I suggest you'd use:

<arg line="${args}"/>

You can check if the property is not set using a specific target with an unless attribute and inside do:

<input message="Type the desired command line arguments:" addProperty="args"/>

Putting it all together gives:

<target name="run" depends="compile, input-runargs" description="run the project">
  <!-- You can use exec here, depending on your needs -->
  <java classname="Main">
    <arg line="${args}"/>
  </java>
</target>
<target name="input-runargs" unless="args" description="prompts for command line arguments if necessary">
  <input addProperty="args" message="Type the desired command line arguments:"/>
</target>

You can use it as follows:

ant
ant run
ant run -Dargs='--help'

The first two commands will prompt for the command-line arguments, whereas the latter won't.