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<TITLE>The Quintessential Logging Program
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<META CONTENT="Patrick Chan" NAME="AUTHOR">
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<B><A HREF="../java.util.logging/pkg.html">java.util.logging</A></B><font color="#666666" SIZE="-2">
[20 examples]
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<h3>
e385.
The Quintessential Logging Program</h3>
To log a message, you first need to obtain a <code>Logger</code> object and then
use it to log the message. Loggers have names that resemble a
fully qualified class name. Typically, log messages generated from a
class would use a <code>Logger</code> with the same name as the class.
<P> The logger contains one or more handlers that are responsible
for processing the log records. A handler could write to a file or
print to a console. Typically, the code that generates log records
should not concern itself with where those log records end up. It only
needs to decide the name of the logger to use.
<P>
This example logs a few messages to a logger.
For examples of controlling the destination of the log messages,
see <a href="../java.util.logging/LogFile.html" class="eglink"><font size="-1"><b>e391</b> Writing Log Records to a Log File</font></a> and
<a href="../java.util.logging/LogConsole.html" class="eglink"><font size="-1"><b>e392</b> Writing Log Records to Standard Error</font></a>.
<pre>
import java.io.*;
import java.util.logging.*;
package <font color="#0066ff"><i>com.mycompany</i></font>;
public class <font color="#0066ff"><i>BasicLogging</i></font> {
public static void main(String[] args) {
// Get a logger; the logger is automatically created if
// it doesn't already exist
Logger logger = Logger.getLogger(<font color="#0066ff"><i>"com.mycompany.BasicLogging"</i></font>);
// Log a few message at different severity levels
logger.severe(<font color="#0066ff"><i>"my severe message"</i></font>);
logger.warning(<font color="#0066ff"><i>"my warning message"</i></font>);
logger.info(<font color="#0066ff"><i>"my info message"</i></font>);
logger.config(<font color="#0066ff"><i>"my config message"</i></font>);
logger.fine(<font color="#0066ff"><i>"my fine message"</i></font>);
logger.finer(<font color="#0066ff"><i>"my finer message"</i></font>);
logger.finest(<font color="#0066ff"><i>"my finest message"</i></font>);
}
}
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Related Examples
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e386. <a class="eglink" href="IsLog.html?l=rel">
Determining If a Message Will Be Logged
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e387. <a class="eglink" href="LogMethod.html?l=rel">
Logging a Method Call
</a>
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e388. <a class="eglink" href="LogExcept.html?l=rel">
Logging an Exception
</a>
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e389. <a class="eglink" href="Minimize.html?l=rel">
Minimizing the Impact of Logging Code
</a>
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e390. <a class="eglink" href="NoParent.html?l=rel">
Preventing a Logger from Forwarding Log Records to its Parent
</a>
<br>
e391. <a class="eglink" href="LogFile.html?l=rel">
Writing Log Records to a Log File
</a>
<br>
e392. <a class="eglink" href="LogConsole.html?l=rel">
Writing Log Records to Standard Error
</a>
<br>
e393. <a class="eglink" href="LogMemory.html?l=rel">
Writing Log Records Only After a Condition Occurs
</a>
<br>
e394. <a class="eglink" href="SetFilter.html?l=rel">
Setting a Filter on a Logger Handler
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See also:
<a class="eglink" href="/egs/java.util.logging/pkg.html?l=rel#Configuration">
Configuration
</a>
<a class="eglink" href="/egs/java.util.logging/pkg.html?l=rel#File%20Size">
File Size
</a>
<a class="eglink" href="/egs/java.util.logging/pkg.html?l=rel#Formatters">
Formatters
</a>
<a class="eglink" href="/egs/java.util.logging/pkg.html?l=rel#Levels">
Levels
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