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Jon Camilleri
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"It is important to note that the Logger returned by one of the getLogger factory methods may be garbage collected at any time if a strong reference to the Logger is not kept."

Sourced from here.


1. Can you confirm that the following code holds a strong reference to the Logger, and, point out any issues where the Garbage Collector Is it possible to tweak the code and use a WeakReference, or would it be an example of overdoing it?
might trip up?
2. I would also like to know whether I can control the size of the file before another file gets created within the rotation sequence of logs.
Within my environment (WinXP/JDK 1.6) the log files are written to c:\documents and settings\%windows user name%
3. How does the code snippet below automatically read the file name (line 121)? How does the parameter reading
mechanism work for say {0}, {1}, {2} etc.?
4. How can I create some code that controls when the logging is switched off and on in a similar fashion of C++ macros.
5. Why does the programmer pass the 2nd parameter (line 87) as "<init>", since this is not written to the log file?
6. Is it possible to update the code, using Reflection classes as parameters to Logger.logp() - see Related link (2) for basic syntax example?
...
logger.logp(Level.INFO, this.getClass().forName(), "ImageViewerFrame()", "test logger"); //this is dummy non-working code
...



Sourced from Core Java Vol.I (8th Ed) P. 584-588 Listing 11.2


Related links
1. E. Nicholas, Understanding weak references
2. Logger logp() example

Log file at C:\Documents and Settings\Jon\LoggingImageViewer.log.0
<?xml version="1.0" encoding="windows-1252" standalone="no"?>
<!DOCTYPE log SYSTEM "logger.dtd">
<log>
<record>
<date>2011-06-05T12:23:56</date>
<millis>1307269436593</millis>
<sequence>0</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINER</level>
<class>ImageViewerFrame</class>
<method><init></method>
<thread>10</thread>
<message>ENTRY</message>
</record>
<record>
<date>2011-06-05T12:23:56</date>
<millis>1307269436625</millis>
<sequence>1</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINER</level>
<class>ImageViewerFrame</class>
<method><init></method>
<thread>10</thread>
<message>RETURN</message>
</record>
<record>
<date>2011-06-05T12:23:56</date>
<millis>1307269436625</millis>
<sequence>2</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINE</level>
<class>LoggingImageViewer$1</class>
<method>run</method>
<thread>10</thread>
<message>Showing frame</message>
</record>
<record>
<date>2011-06-05T12:31:19</date>
<millis>1307269879671</millis>
<sequence>3</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINER</level>
<class>ImageViewerFrame.FileOpenListener</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>ENTRY java.awt.event.ActionEvent[ACTION_PERFORMED,cmd=Open,when=1307269879671,modifiers=Button1] on javax.swing.JMenuItem[,1,3,51x21,invalid,alignmentX=0.0,alignmentY=0.0,border=javax.swing.plaf.metal.MetalBorders$MenuItemBorder@131f71a,flags=264,maximumSize=,minimumSize=,preferredSize=,defaultIcon=,disabledIcon=,disabledSelectedIcon=,margin=javax.swing.plaf.InsetsUIResource[top=2,left=2,bottom=2,right=2],paintBorder=true,paintFocus=false,pressedIcon=,rolloverEnabled=false,rolloverIcon=,rolloverSelectedIcon=,selectedIcon=,text=Open]</message>
</record>
<record>
<date>2011-06-05T12:31:40</date>
<millis>1307269900437</millis>
<sequence>4</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINE</level>
<class>ImageViewerFrame$FileOpenListener</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>Reading file C:\Documents and Settings\Jon\My Documents\My Archives\My Pictures\chat\rita26-3.jpg</message>
</record>
<record>
<date>2011-06-05T12:31:40</date>
<millis>1307269900515</millis>
<sequence>5</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINER</level>
<class>ImageViewerFrame.FileOpenListener</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>RETURN</message>
</record>
<record>
<date>2011-06-05T12:31:43</date>
<millis>1307269903390</millis>
<sequence>6</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINER</level>
<class>ImageViewerFrame.FileOpenListener</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>ENTRY java.awt.event.ActionEvent[ACTION_PERFORMED,cmd=Open,when=1307269903390,modifiers=Button1] on javax.swing.JMenuItem[,1,3,51x21,invalid,alignmentX=0.0,alignmentY=0.0,border=javax.swing.plaf.metal.MetalBorders$MenuItemBorder@131f71a,flags=264,maximumSize=,minimumSize=,preferredSize=,defaultIcon=,disabledIcon=,disabledSelectedIcon=,margin=javax.swing.plaf.InsetsUIResource[top=2,left=2,bottom=2,right=2],paintBorder=true,paintFocus=false,pressedIcon=,rolloverEnabled=false,rolloverIcon=,rolloverSelectedIcon=,selectedIcon=,text=Open]</message>
</record>
<record>
<date>2011-06-05T12:32:04</date>
<millis>1307269924000</millis>
<sequence>7</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINE</level>
<class>ImageViewerFrame$FileOpenListener</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>Reading file C:\Documents and Settings\Jon\My Documents\My Archives\New car (july 2010)\uktomalta.com - Mazda 3 1.6D TS Hatchback (2008) - 21.07.2010.pdf</message>
</record>
<record>
<date>2011-06-05T12:32:04</date>
<millis>1307269924109</millis>
<sequence>8</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINER</level>
<class>ImageViewerFrame.FileOpenListener</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>RETURN</message>
</record>
<record>
<date>2011-06-05T12:32:07</date>
<millis>1307269927187</millis>
<sequence>9</sequence>
<logger>com.horstmann.corejava</logger>
<level>FINE</level>
<class>ImageViewerFrame$1</class>
<method>actionPerformed</method>
<thread>10</thread>
<message>Exiting.</message>
</record>
</log>








 
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