How to access SerialPort in Applets using jSSC library

[eswari Malluru]

Hi,

I have a requirement to access serial ports from Applets. For this using jssc.jar library and try to get the list of available ports. When I am doing this getting the below exception

Exception in thread "Thread-23" java.lang.ExceptionInInitializerError
at jssc.SerialPortList.<clinit>(SerialPortList.java:43)
at SerialIO.fetchSerialPorts(SerialIO.java:204)
at Applet.startJavaScriptListener(Applet.java:174)
at Applet.mav$startJavaScriptListener(Applet.java:36)
at Applet$1.run(Applet.java:105)
at java.security.AccessController.doPrivileged(Native Method)
at printer.Applet.run(Applet.java:100)
at java.lang.Thread.run(Unknown Source)
Caused by: java.security.AccessControlException: access denied ("java.util.PropertyPermission" "user.home" "read")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at sun.awt.AWTSecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
at java.lang.System.getProperty(Unknown Source)
at jssc.SerialNativeInterface.<clinit>(SerialNativeInterface.java:85)
... 8 more

How should I modify the java.policy to get out of this exception. Do I need to use anything else other than this jar.

I am using java 1.6.0_27 and Windows 7

Please help me in resolving this issue.

Thanks,
Eshwari

[Tony Docherty]

The answer to your question is in the stack trace:

access denied ("java.util.PropertyPermission" "user.home" "read")

In your policy file you need to set the property permission for user.home to allow read access.

Something like:

grant codeBase "file:mycodebase/*" {
  permission java.util.PropertyPermission "user.home", "read";                       
};

[victor sre]

To handle permission, scm uses tmp folder. The scm is an alternative library to rxtx/javaxcom.
Wiki : http://www.embeddedunveiled.com/
Repository : https://github.com/RishiGupta12/serial-communication-manager
Video : https://www.youtube.com/watch?v=fYLQbelGunQ

It supports RS-232 control signals handshaking, monitoring and has been ported to Linux, MAC, Solaris and Windows operating system. It is consistent, portable, efficient, reliable, testable, extensible, modifiable, scalable library.