If you are using any frameworks other than the Apple-provided WebObjects frameworks that include client-side classes, you will need to manually copy the framework's client-side .jar files into your project's WebServerResources/Java directory (and remember to always update them) or have Ant automatically copy them there when building/installing by modifying the build.xml and javaclientbuild.xml files to go grab all the client-side jar files from the local frameworks directory (Usually /Library/Frameworks) using the following addition:

<!-- the Java Client Client-Side Classes 	  -->
<copy todir="${dest.dir}/${project.name}/WEB-INF/${project.name}.woa/Contents/WebServerResources/Java">
	<fileset dir="${wo.wolocalroot}/Library/Frameworks"> 
		<include name="**/WebServerResources/Java/*.jar"/> 
	</fileset> 
	<mapper type="flatten"/>
</copy>

Either way, you will also need to add an entry to the project's ClasspathClient.txt file for each one.

WebObjects seems to be able to find its own client-side classes from within the Library/Frameworks directory, but it cannot find any others.

For example, I have a framework named MyFoundation.framework that has a couple classes in it that are used by the client-side of my application. In order for WO to find these classes, they must be in a Jar located in the MyApp.woa/Contents/WebServerResources/Java/. You will then need to make sure that the ClasspathClient.txt classpath file has an entry pointing to it like so:

APPROOT/WebServerResources/Java/MyFoundation.jar

You can also