com/hp/hpl/jena/shared/PrefixMapping$IllegalPrefixException

[Carmen Manzulli]

Hi experts,

i'm trying to use some jena classes (as Query and QueryFactory) in a
project  but when i run my code i get:

 java.lang.NoClassDefFoundError:
com/hp/hpl/jena/shared/PrefixMapping$IllegalPrefixException
        at com.hp.hpl.jena.query.QueryFactory.create(QueryFactory.java:68)
        at com.hp.hpl.jena.query.QueryFactory.create(QueryFactory.java:40)
        at com.hp.hpl.jena.query.QueryFactory.create(QueryFactory.java:28)
        at sisinflab.Query2.compute(Query2.java:27)

and also :

java.lang.ClassNotFoundException:
com.hp.hpl.jena.shared.PrefixMapping$IllegalPrefixException
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        ... 12 more

who can help me?