The FileHandler class supports filename patterns. : Log « Log « Java Tutorial

The FileHandler class allows the substitution of paths such as the user's home directory or the system's temporary directory.

The forward slash (/) is used as a directory separator/

The forward slash (/) works for both Unix and Windows machines.

The FileHandler class supported to specify where the generation number goes in the filename when log files are rotated.

These patterns are each prefixed with a percent sign (%).

To include the percent sign in the filename, specify two percent signs (%%).

The following table contains all the valid percent-sign substitutions.

%tFull path of the system temporary directory
%hValue of the user.home system property
%gGeneration number used to distinguish rotated logs
%uUnique number used to resolve process conflicts

35.1.1.A full list of levels.
35.1.2.Logging a Method Call
35.1.3.Logging an Exception
35.1.4.The StreamHandler serves chiefly as a base class for all handlers that write log messages to some OutputStream.
35.1.5.The ConsoleHandler writes log messages to System.err.
35.1.6.The SocketHandler writes log messages to the network over a specified TCP port.
35.1.7.The FileHandler is able to write to a single file, or write to a rotating set of files as each file reaches a specified maximum size.
35.1.8.The FileHandler class supports filename patterns.
35.1.9.The MemoryHandler is a circular buffer in memory.
35.1.10.The ErrorManager
35.1.11.Information Logging
35.1.12.Log to a file
35.1.13.Guaranteeing proper class and method names
35.1.14.Preventing a Logger from Forwarding Log Records to Its Parent