Java Reference
In-Depth Information
•
Specifying all Java-related information, such as the classpath, standard output, main
class, execution parameters, and other various properties to be added to the Java environ-
ment, and so on.
•
Security issues. It is possible, for instance, to modify the
-verify
/
-verifyremote
com-
mand-line switches for the JVM, or modify OS' settings for the firewall, HTTP proxy,
and so on.
JBindery can work as a launcher only— to launch the Java class on the Mac OS without pack-
aging it.
PLC's JOVE
PLC's JOVE is a translator of bytecode that essentially transforms your Java executable into
native Wintel code. To do so, it adds a little runtime support to the package, together with the
translated program to be executed natively by the runtime support. In the translation and pack-
aging support, the code is optimized to additionally enhance the performance. The outcome is
a single platform-dependent executable. This solution is quite different from the other packager
utilities, in that it translates the code, too, changing it deeply. The advantage is fast perfor-
mance, but there are also drawbacks, such as limitations in supporting all Java bytecode
instructions. For example, dynamic loading of classes is not supported. Before translating a
Java executable this way, you have to run a verifier utility to see if the program can be trans-
lated into native code with this technology.
Other Java Deployment Means
In this section, we examine other interesting Java technologies related to deployment.
Mobile Agents
Defining mobile agent software is not simple; there are many slightly different definitions, and
the whole topic is still evolving as an experimental technology. To shed some light on this
promising Java phenomenon we will introduce it briefly here, and we will mention one prod-
uct.
Briefly, we can say that a mobile agent is software that is
• goal-driven, or as they like to say, proactive.
• autonomous. It can be left working on its own, reacting to changes and events from out-
side.
• able to communicate with other agents.
• mobile. It can move from one host computer to another one.
• adaptive. It can adapt its behavior based on its own past experience.
