Integration

Hi, I'm a beginner on Weblogic, sorry my so simple and basic question (and my bad english). But I'm trying to build the weblogic examples ("ant build", as the documentation says) and got error messages like this:

Buildfile: build.xml

clean:

init:
mkdir Created dir: /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30/build/META-INF
copy Copying 1 file to /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30/build/META-INF
copy Copying 1 file to /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30/build/META-INF
echo ======================================================
echo Building EJB 3.0 Samples
echo ======================================================
echo Base directory : /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30
echo Samples Home : /opt/bea/wlserver_10.3/samples
echo Deployed Target : /opt/bea/wlserver_10.3/samples/server/examples/build/ejb30/reviewService.ear

compile:
javac Compiling 38 source files to /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30/build
javac /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30/src/java/examples/ejb/ejb30/domain/Artist.java:6: package javax.persistence does not exist
javac import javax.persistence.*;
javac ^
javac /opt/bea/wlserver_10.3/samples/server/examples/src/examples/ejb/ejb30/src/java/examples/ejb/ejb30/domain/Person.java:7: package javax.persistence does not exist

(...)

I suppose that there is some "jar" containing "javax.persistence" that should be included in some classpath
on build.xml file, but I didn't find such "jar". I found in documentation that persistence is also implemented using
the Kodo software, an may be I should configure it, but I don't know how. Can someone help me building the
Weblogic examples?

Thanks.