Modifying the Ant Classpath
  When using an optional or custom task it is usually necessary to add extra libraries to the classpath. The Ant
  classpath can be modified globally or per launch configuration.
  To modify the Ant classpath globally:
  
    - Open the 
     Ant > Runtime
    preference page. Ant > Runtime
    preference page.
- If you are not on it already, click the Classpath tab.
 
  
- To add a JAR file to the classpath, click Add Jar and select the JAR file.
- To add a folder to the classpath, click Add Folder and select the folder.
- To remove an item from the classpath, select it and click Remove.
- To restore the classpath to the default, click Restore Defaults.
To modify the Ant classpath for a launch configuration:
  
    - Click  Run > External Tools > External
    Tools.... Run > External Tools > External
    Tools....
- Select the Ant configuration whose classpath you wish to modify
- Select the Classpath tab
 
  
- To add a JAR file to the classpath, click Add Jar and select the JAR file.
- To add a folder to the classpath, click Add Folder and select the folder.
- To remove an item from the classpath, select it and click Remove.
Ant support
  External tools
  Running Ant buildfiles
  Running external tools