Add a "java" command to the CLI, using the same syntax of java.so and
attempting to emulate as closely as possible the "java" command on Linux.
So for example one can run

        java Hello

to run /java/Hello.class (/java is on the classpath by default), or

        java -jar /java/bench.jar

to run the main class of this jar, or a more sophisticated
command lines, such as the following which runs Jetty (if the
appropriate files are in your image):

        java -classpath /jetty/* org.eclipse.jetty.xml.XmlConfiguration /jetty/jetty.xml

Note that like java.so, the new "java" command basically runs the RunJava
class (/java/RunJava.class). Remember that java.so adds /java to the parent
class loader, so we can always find the RunJava class even though it's not
in cli.jar or cloudius.jar).