Writing Diagnostics to Standard Output and Error Streams

An applet can write messages to the standard output and standard error streams. Writing diagnostics to standard output can be an invaluable tool when you are debugging an applet.

The following code snippet writes messages to the standard ouput stream and the standard error stream.

//Where instance variables are declared:
boolean DEBUG = true;
. . .
//Later, when we want to print some status:
if (DEBUG) {
    try {
        ... //some code that throws an exception
        System.out.println("Called someMethod(" + x + "," + y + ")");
    } catch (Exception e) {
        e.printStackTrace()
    }
}

Check the Java Console log for messages written to the standard output stream or standard error stream. To store messages in a log file, enable logging in the Java Control Panel. Messages will be written to a log file in the user's home directory (for example, on Windows, the log file might be in C:\Documents and Settings\someuser\Application Data\Sun\Java\Deployment\log).