Class SimpleFormatter

java.lang.Object
java.util.logging.Formatter
java.util.logging.SimpleFormatter
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 format the log messages. This property can be defined in the 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 illegal, the default format is implementation-specific.

Since:
1.4
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    SimpleFormatter()
    Create a SimpleFormatter.

  • Method Summary

    Modifier and Type
    Method
    Description
    String
    format(LogRecord record)
    Format the given LogRecord.

    Methods declared in class Formatter

    formatMessage, getHead, getTail
    Modifier and Type
    Method
    Description
    String
    formatMessage(LogRecord record)
    Localize and format the message string from a log record.
    String
    getHead(Handler h)
    Return the header string for a set of formatted records.
    String
    getTail(Handler h)
    Return the tail string for a set of formatted records.

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
    boolean
    equals(Object o)
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    May cause performance issues, deadlocks and hangs.
    final Class<? extends Object>
    getClass()
    Answers the unique instance of java.lang.Class which represents the class of the receiver.
    int
    hashCode()
    Answers an integer hash code for the receiver.
    final void
    notify()
    Causes one thread which is waiting on the receiver to be made ready to run.
    final void
    notifyAll()
    Causes all threads which are waiting on the receiver to be made ready to run.
    String
    toString()
    Answers a string containing a concise, human-readable description of the receiver.
    final void
    wait()
    Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
    final void
    wait(long time)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
    final void
    wait(long time, int frac)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

  • Constructor Details

    • SimpleFormatter

      public SimpleFormatter()
      Create a SimpleFormatter.

  • Method Details

    • format

      public 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 ZonedDateTime object representing event time of the log record in the ZoneId.systemDefault() system time zone.
      3. source - a string representing the caller, if available; otherwise, the logger's name.
      4. logger - the logger's name.
      5. level - the 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 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 by 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(MyClass.java:9)
            at MyClass.crunch(MyClass.java:6)
            at MyClass.main(MyClass.java:3)
      • 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
      • java.util.logging.SimpleFormatter.format="%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS.%1$tN %1$Tp %2$s%n%4$s: %5$s%6$s%n"

        Since JDK 9, java.util.logging uses java.time to create more precise time stamps. The format above can be used to add a .%1$tN to the date/time formatting so that nanoseconds will also be printed: 

            Feb 06, 2015 5:33:10.279216000 PM example.Main main
    INFO: This is a test

      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.

      Specified by:
      format in class Formatter
      Parameters:
      record - the log record to be formatted.
      Returns:
      a formatted log record