I found this out....
Under the projects Dir there is a hidden XML file called .classpath, so I added the ones in bold to the file:
<?xml version="1.0" encoding="UTF-8"?>
<classpath>
<classpathentry kind="src" path="src"/>
<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/classes12.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/classes12_g.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/ojdbc14.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/ojdbc14_g.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/classes12dms.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/classes12dms_g.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/classes111.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/classes111_g.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/nls_charset11.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/nls_charset12.jar"/>
<classpathentry kind="lib" path="/opt/oracle/product/10gR2/jdbc/lib/ocrs12.jar"/>
<classpathentry kind="output" path="bin"/>
</classpath>
And now it works. I have no read this in any other forum nor book, tutorial. I simply tried.
Thank you.