public class SimpleFormatter extends Formatter

Print a brief summary of the LogRecord in a human readable format. The summary will typically be 1 or 2 lines.

Configuration: The SimpleFormatter is initialized with the format string specified in the java.util.logging.SimpleFormatter.format property to {@linkplain #format format} the log messages. This property can be defined in the {@linkplain LogManager#getProperty logging properties} configuration file or as a system property. If this property is set in both the logging properties and system properties, the format string specified in the system property will be used. If this property is not defined or the given format string is {@linkplain java.util.IllegalFormatException illegal}, the default format is implementation-specific.

See Also

Public Constructor Summary

Public Method Summary

synchronized String
format(LogRecord record)
Format the given LogRecord.

Inherited Method Summary

Public Constructors

public SimpleFormatter ()

Public Methods

public synchronized String format (LogRecord record)

Format the given LogRecord.

The formatting can be customized by specifying the format string in the java.util.logging.SimpleFormatter.format property. The given LogRecord will be formatted as if by calling:

    String.format(format, date, source, logger, level, message, thrown);
where the arguments are:
  1. format - the java.util.Formatter format string specified in the java.util.logging.SimpleFormatter.format property or the default format.
  2. date - a Date object representing {@linkplain LogRecord#getMillis event time} of the log record.
  3. source - a string representing the caller, if available; otherwise, the logger's name.
  4. logger - the logger's name.
  5. level - the {@linkplain Level#getLocalizedName log level}.
  6. message - the formatted log message returned from the Formatter.formatMessage(LogRecord) method. It uses java.text formatting and does not use the java.util.Formatter format argument.
  7. thrown - a string representing the {@linkplain LogRecord#getThrown throwable} associated with the log record and its backtrace beginning with a newline character, if any; otherwise, an empty string.

Some example formats:

  • java.util.logging.SimpleFormatter.format="%4$s: %5$s [%1$tc]%n"

    This prints 1 line with the log level (4$), the log message (5$) and the timestamp (1$) in a square bracket.

         WARNING: warning message [Tue Mar 22 13:11:31 PDT 2011]
  • java.util.logging.SimpleFormatter.format="%1$tc %2$s%n%4$s: %5$s%6$s%n"

    This prints 2 lines where the first line includes the timestamp (1$) and the source (2$); the second line includes the log level (4$) and the log message (5$) followed with the throwable and its backtrace (6$), if any:

         Tue Mar 22 13:11:31 PDT 2011 MyClass fatal
         SEVERE: several message with an exception
         java.lang.IllegalArgumentException: invalid argument
                 at MyClass.mash(
                 at MyClass.crunch(
                 at MyClass.main(
  • java.util.logging.SimpleFormatter.format="%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp %2$s%n%4$s: %5$s%n"

    This prints 2 lines similar to the example above with a different date/time formatting and does not print the throwable and its backtrace:

         Mar 22, 2011 1:11:31 PM MyClass fatal
         SEVERE: several message with an exception

This method can also be overridden in a subclass. It is recommended to use the Formatter.formatMessage(LogRecord) convenience method to localize and format the message field.

record the log record to be formatted.
  • a formatted log record