Server-Side Java - Java - page 673

As with log4j , every Logger object has a given logging level, and messages below that
level are silently discarded:

public public void void setLevel ( java . util . logging . Level );

public public java . util . logging . Level getLevel ( );

public public boolean boolean isLoggable ( java . util . logging . Level );

As with log4j , objects handle the writing of the log. Each logger has a Handler :

public public synchronized synchronized void void addHandler ( java . util . logging . Handler );

public public synchronized synchronized void void removeHandler ( java . util . logging . Handler );

public public synchronized synchronized java . util . logging . Handler [] getHandlers ( );

and each Handler has a Formatter , which formats a LogRecord for display. By providing
your own Formatter , you have more control over how the information being passed into the
log gets formatted.

Unlike log4j , the Java SE logging mechanism has a default configuration, so
Example 16-13 is a minimal logging example program.

Example 16-13. Log14Demo.java
public public class class Log14Demo Log14Demo {

public public static static void void main ( String [] args ) {

Logger myLogger = Logger . getLogger ( "com.darwinsys" );

Object o = new new Object ();

myLogger . info ( "I created an object: " + o );

}

}

Running it prints the following:

C:> java logging.Log14Demo
Mar 8, 2014 7:48:26 PM Log14Demo main
INFO: I created an object: java.lang.Object@57f0dc
C:>

As with log4j , the typical use is in logging caught exceptions; the code for this is in
Example 16-14 .