From the J2EE tutorial:
"To run the asant scripts, you must set common build properties in the file <INSTALL>/j2eetutorial14/examples/common/build.properties as follows:
Set the j2ee.home property to the location of your Application Server installation. The build process uses the j2ee.home property to include the libraries in <J2EE_HOME>/lib/ in the classpath. All examples that run on the Application Server include the J2EE library archive--<J2EE_HOME>/lib/j2ee.jar--in the build classpath. Some examples use additional libraries in <J2EE_HOME>/lib/ and <J2EE_HOME>/lib/endorsed/; the required libraries are enumerated in the individual technology chapters. <J2EE_HOME> refers to the directory where you have installed the Application Server or the J2EE 1.4 SDK.
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Note: On Windows, you must escape any backslashes in the j2ee.home property with another backslash or use forward slashes as a path separator. So, if your Application Server installation is C:\Sun\AppServer, you must set j2ee.home as follows:
j2ee.home = C:\\Sun\\AppServer
or
j2ee.home=C:/Sun/AppServer
"