Using the Preferences page, you can direct the workbench to use a specific runtime environment of an application server for compiling your application. You can complete this by defining the installation directory of the server:
To change the list of available target servers, click Window > Preferences > Server > Installed Runtimes to go to the Installed Server Runtime Environments section of the Preferences dialog. Use the Add, Edit, Remove or Search options to change the list of target servers as needed.