Java Tracing & logging

Reference from: http://java.sun.com/javase/6/docs/technotes/guides/deployment/deployment-guide/tracing_logging.html

Tracing

Tracing is a facility to redirect any output in the Java Console to a trace file.

Java Plug-in

Tracing can be turned on by enabling the property javaplugin.trace. However, it turns on all tracing facilities inside Java Plug-in. To enable more fine-grained tracing, javaplugin.trace.option may be used. You can set trace-level options (0-5) in the Java Console, shown in the previous chapter, with the following meanings:

• 0 — off
• 1 — basic
• 2 — network, cache, and basic
• 3 — security, network and basic
• 4 — extension, security, network and basic
• 5 — LiveConnect, extension, security, network, temp, and basic

This enables tracing on the fly.

Another way to set fine-grained tracing is through the Java Control Panel. For instance, to enable tracing for everthing (option 5 above), enter the following in the "Java Run Time Parameters" textfield:

-Djavaplugin.trace=true
-Djavaplugin.trace.option=basic|net|cache|security|ext|liveconnect|temp

Tracing set through the Control Panel will take effect when the Plug-in is launched, but changes made through the Control Panel while a Plug-in is running will have no effect until restart.

Java Web Start

To set the initial trace level for a Java Web Start application set the deployment property deployment.trace.level. The deployment.trace.level property can have one of the following values:

• basic
• cache
• net
• security
• ext
• liveconnect

To use all the tracing level set deployment.trace.level to all.

Logging

Similar to tracing, logging is a facility to redirect any output in the Java Console to a log file using the Java Logging API. To enable logging perform the following actions:

• Open Java Control Panel
• Click Advanced tab.
• Select Enable Logging under the Debugging option

Other Options

File Names

The names of the trace and log files are

plugin.trace
plugin.log

where the includes the major, minor and patch version numbers; e.g., plugin142_06.trace or plugin150.log

File Locations

The default location (directory) of the trace and log files is:

• /.java/deployment/log on Unix/Linux
• \Sun\Java\Deployment\log on Windows

where is as defined here.

If the environment variable USER_JPI_PROFILE is set to then the trace and log files will be written to:

• /.java/deployment/log on Unix/Linux
• \Sun\Java\Deployment\log on Windows