FileHandler defines more fields, including %t and %g. FileHandler code replaces occurrences of the %t field in the name pattern with the system temporary directory. On Windows, this is usually c:\temp; on Unix, this is usually /tmp. The FileHandler code replaces occurrences of the %g field with a generation number. You use this field in conjunction with the java.util.logging.File-Handler.count (I'll refer to this as the shortened property-name count) and java.util.logging.FileHandler.limit (limit) properties. The limit property represents how many bytes will be stored in a log file before it reaches its limit. A limit value of 0 means there is no limit. When a log file reaches its limit, the FileHandler object closes it. The count field specifies how many log files that FileHandler cycles through. If the value of count is 1, the FileHandler will reuse the same log file each time it reaches its limit. Otherwise the FileHandler tracks a generation number. The first log file uses a generation number of 0 in place of the %g field. With a log filename pattern of java%g.log, the first generated log filename is java0.log. Each time a log file reaches capacity, the FileHandler bumps up the generation number and uses this to replace the %g field in the filename pattern. The FileHandler writes subsequent log entries to the log file with this new name. The second log file is java1.log. Once the FileHandler closes count log files, it resets the generation number to 0. |