Serial Programming - upload.wikimedia....

Using Java for Serial Communication
• one as part of the private JRE which comes with the JDK to run JDK tools, and
• one as part of the public JRE which comes with the JDK to run applications
Some even claim to have a fourth JRE somewhere in the \Windows directory hierarchy.
JavaComm should at least be installed as extension in the JDK and in all public JREs.
Webstart
JavaComm
A general problem, both for JavaComm and RxTx is, that they resist installation via Java
WebStart 4 :
JavaComm is notorious, because it requires a file called javax.comm.properties to be placed in
the JDK lib directory, something which can't be done with Java WebStart. This is particularly
sad, because the need for that file is the result of some unnecessary design/decision in
JavaComm and could have easily been avoided by the JavaComm designers. Sun constantly
refuses to correct this error, citing the mechanism is essential. Which is, they are lying
through their teeth when it comes to JavaComm, particular, because Java for a long time
has a service provider architecture exactly intended for such purposes.
The contents of the properties file is typically just one line, the name of the java class with
the native driver, e.g.:
driver=com.sun.comm.Win32Driver
The following is a hack which allows to deploy JavaComm via Web Start ignoring that
brain-dead properties file. It has serious drawbacks, and might fail with newer JavaComm
releases - should Sun ever come around and make a new version.
First, turn off the security manager. Some doofus programmer at Sun decided that it would
be cool to again and again check for the existence of the dreaded javax.comm.properties file,
even after it has been loaded initially, for no other apparent reason than checking for the file.
System.setSecurityManager(null);
Then, when initializing the JavaComm API, initialize the driver manually:
String driverName = "com.sun.comm.Win32Driver"; // or get as a JNLP
property
CommDriver commDriver =
(CommDriver)Class.forName(driverName).newInstance();
commDriver.initialize();
RxTx
4 http://java.sun.com/products/javawebstart/
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