Debugging Java classes

The MobiLink server writes messages to a message log file. The server log file contains the following information:

The Java Runtime Environment. You can use the -jrepath option to request a particular JRE when you start the MobiLink server. The default path is the path of the JRE installed with SQL Anywhere 12.
The path of the standard Java classes loaded. If you did not specify these explicitly, the MobiLink server automatically adds them to your classpath before invoking the Java VM.
The fully specified names of the specific methods invoked. You can use this information to verify that the MobiLink server is invoking the correct methods.
Any output written in a Java method to java.lang.System.out or java.lang.System.err is redirected to the MobiLink server log file.
The mlsrv12 command line option -verbose can be used.

See -v mlsrv12 option.

You can debug your Java classes using a standard Java debugger. Specify the necessary parameters using the -sl java option on the mlsrv12 command line.

See -sl java mlsrv12 option.

Specifying a debugger causes the Java VM to pause and wait for a connection from a Java debugger.

Alternatively, you may choose to add statements to your Java methods that print information to the MobiLink message log, using java.lang.System.err or java.lang.System.out. Doing so can help you track the progress and behavior of your classes.

Performance tip

Printing information in this manner is a useful monitoring tool, but is not recommended in a production scenario.

The same technique can be exploited to log arbitrary synchronization information or collect statistical information on how your scripts are used.

You may want to write your own driver to exercise your Java classes. This approach can be helpful because it isolates the actions of your Java methods from the rest of the MobiLink system.

Debugging Java classes

Information in the MobiLink server's log file

Using a Java debugger

Printing information from Java

Performance tip

Writing your own test driver