Weblogic's servicegen "takes as input an EJB JAR file or list of Java classes, and creates all the needed Web Service components and packages them into a deployable EAR file".
javaClassComponents has as input a "Comma-separated list of Java class names that implement the Web Service operation. The Java classes must be compiled and in your CLASSPATH"
This comes under the service element of servicegen so part of the build.xml would be:
So in the CLASSPATH, you would have:
and Java_ServiceImpl.java would than have a:
Note the "a_service.service" in javaClassComponents. If that's missing, servicegen will invoke javac which will then throw a "Class not found" exception.
But where does the Java class come from in the first place? See this