A Java 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 a Java 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
).
Be sure to disable all debugging output before you release your applet.