Problem with creating FileHandler

From:

"Rhino" <no.offline.contact.please@example.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 23 Feb 2010 16:42:01 -0500

Message-ID:

<hm1i3e$bho$1@news.datemas.de>

Hi,

I am having an odd problem using Ant. Whenever my Java program tries to
create a new instance of java.util.logging.FileHandler, I get a
java.io.IOException that says "Couldn't get lock for log2\baz.log.xml".

The weird part of this problem is that I get this error when I am running
Ant but NOT when I simply execute the program in Eclipse.

I am running Eclipse 3.5.1 Galileo on Windows XP with SP 2. This version of
Eclipse contains Ant 1.7.1.

When I run the program from an Ant script within Eclipse OR from the Windows
command line (using Ant 1.8.0), I get the error that I mentioned. However,
when I run the program as a Java application from within Eclipse, it works
fine and does not generate this error.

I'm baffled and would appreciate some help to prevent this error.

I've created a simple example and an Ant build file that illustrates the
problem.

My project is called Logging and it is a regular Java project in Eclipse.
Within the package com.foo.baz2, which is in my src folder in the Logging
project, I have the following classes:

   * Supremo, which is the driver program
   * Alpha, which is the class invoked from Supremo which actually
     writes to the log file

Here is the source code for Supremo:
================================
package com.foo.baz2;

import java.io.File;
import java.io.IOException;
import java.util.logging.FileHandler;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Supremo {
   /**
    * The name of this class.
    */
   private final String CLASS_NAME = getClass().getName();

   /**
    * The logger that will log error messages in this class.
    */
   private Logger logger = null;
     /**
    * The file handler used by this logger.
    */
   private Handler logFileHandler = null;

   /**
    * @param args
    */
   public static void main(String[] args) {
             new Supremo();
             System.out.println("=== Supremo ends ===");
   }
     public Supremo() {
             configureLogger(); new Alpha(logger).writeText();
   }

  /**
    * Method configureLogger() configures the logger(s) used by this
program.
    *
    * <p>Additional comments about method configureLogger().</p>
    */
   private final void configureLogger() {

       String METHOD_NAME = "configureLogger()"; //$NON-NLS-1$
             /* Create the logger. */ this.logger =
Logger.getLogger(CLASS_NAME);
         /* Create a file handler for the logger. */
       String logFile = "log2" + File.separator + "baz.log.xml";
       try {
           this.logFileHandler = new FileHandler(logFile);
           }
       catch (IOException io_excp) {
           System.err.println(this.CLASS_NAME + "." + METHOD_NAME + " -
Couldn't create FileHandler for logger " + this.CLASS_NAME + " using file "
+ logFile + ". Error: " + io_excp); //$NON-NLS-1$ //$NON-NLS-2$
//$NON-NLS-3$ //$NON-NLS-4$
           io_excp.printStackTrace();
           return;
           }
       this.logger.addHandler(this.logFileHandler);
         /* Set the logging level. */
this.logger.setLevel(Level.FINEST);
   }

}
================================

Here is the source code for Alpha:

================================
package com.foo.baz2;

import java.util.logging.Logger;

public class Alpha {

   /**
    * The name of this class.
    */
   private final String CLASS_NAME = getClass().getName();

   /**
    * The logger that will log error messages in this class.
    */
   private Logger logger = null;
     public Alpha() {
       super();
   }
     public Alpha(Logger logger) {
       super();
       this.logger = logger;
   }
     public void writeText() {
             final String METHOD_NAME = "writeText()";
             System.out.println(CLASS_NAME);
       logger.entering(CLASS_NAME, METHOD_NAME);
         } }
================================

Here is the build file, which is named build2.xml:

================================
<?xml version="1.0" ?><project name="Logging" default="buildall"
basedir=".">
<description>Compile and run the Baz program.
</description>

<property name="domain.slashes" value="com\foo" description="The domain name
written as a path."/>
<property name="jdkbin" value="c:\Program Files\Java\jdk1.6.0_18\bin"
description="The path to the Java JDK binaries."/>
<property name="workspace351" value="c:\eclipse\workspace" description="The
path to the Eclipse 3.5.1 workspace."/>
<property name="baz.proj" value="Logging" description="The name of the Baz
project."/>
<property name="baz.pkg" value="${domain.slashes}\baz2" description="The
name of the package containing the Baz code."/>
<property name="compiler.path" value="${jdkbin}\javac" description="The path
of the Java 1.6.0_18 compiler."/>
<property name="baz.src" value="${workspace351}\${baz.proj}\src"
description="The path to the source files for the Baz code."/>
<property name="baz.bin" value="${workspace351}\${baz.proj}\bin"
description="The path to the class files for the Baz code."/>
<property name="baz.output.dir" value="${workspace351}\${baz.proj}\output"
description="The path to the output directory for the Baz project."/>


<patternset id="ps.baz" description="The project-specific Baz code.">
   <include name="${baz.pkg}\*.*"/>
   </patternset>

<target name="compile" description="Compile the Java code.">
   <javac srcdir="${baz.src}" destdir="${baz.bin}" compiler="modern"
fork="yes"
       verbose="no" debug="on" debuglevel="lines,vars,source"
deprecation="yes"
       executable="${compiler.path}" source="1.6"
       description="Compile the code in the baz packages.">
       <classpath>
           <pathelement path="${baz.bin}"/>
           </classpath>
       <patternset refid="ps.baz"/>
       </javac>
</target>


<target name="run" description="Run the program.">
     <echo message="Run the program."/>
   <java classname="com.foo.baz2.Supremo" fork="false"
       description="Execute the Supremo program.">
       <classpath>
           <pathelement path="${baz.bin}"/>
           </classpath>
       </java>
      </target>


<target name="buildall" depends="compile,run" description="Tasks that make
up a complete build.">
   <echo message="The build has ended successfully."/>
</target>
</project>
================================

Here is the output from the Ant build when it is run in Eclipse using Ant
1.7.1:

================================
Buildfile: C:\eclipse\workspace\Logging\xml\build2.xml
compile:
run:
    [echo] Run the program.
    [java] com.foo.baz2.Supremo.configureLogger() - Couldn't create
FileHandler for logger com.foo.baz2.Supremo using file log2\baz.log.xml.
Error: java.io.IOException: Couldn't get lock for log2\baz.log.xml
    [java] java.io.IOException: Couldn't get lock for log2\baz.log.xml
    [java] at java.util.logging.FileHandler.openFiles(Unknown Source)
    [java] at java.util.logging.FileHandler.<init>(Unknown Source)
    [java] at com.foo.baz2.Supremo.configureLogger(Supremo.java:61)
    [java] at com.foo.baz2.Supremo.<init>(Supremo.java:40)
    [java] at com.foo.baz2.Supremo.main(Supremo.java:33)
    [java] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
    [java] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown
Source)
    [java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown
Source)
    [java] at java.lang.reflect.Method.invoke(Unknown Source)
    [java] at
org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
    [java] at
org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
    [java] at org.apache.tools.ant.taskdefs.Java.run(Java.java:764)
    [java] at
org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:218)
    [java] at
org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:132)
    [java] at org.apache.tools.ant.taskdefs.Java.execute(Java.java:105)
    [java] at
org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    [java] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
    [java] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown
Source)
    [java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown
Source)
    [java] at java.lang.reflect.Method.invoke(Unknown Source)
    [java] at
org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    [java] at org.apache.tools.ant.Task.perform(Task.java:348)
    [java] at org.apache.tools.ant.Target.execute(Target.java:357)
    [java] at org.apache.tools.ant.Target.performTasks(Target.java:385)
    [java] at
org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    [java] at
org.apache.tools.ant.Project.executeTarget(Project.java:1306)
    [java] at
org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
    [java] at
org.eclipse.ant.internal.ui.antsupport.EclipseDefaultExecutor.executeTargets(EclipseDefaultExecutor.java:32)
    [java] at
org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    [java] at
org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.run(InternalAntRunner.java:423)
    [java] at
org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.main(InternalAntRunner.java:137)
    [java] com.foo.baz2.Alpha
    [java] com.foo.baz2.Beta
    [java] com.foo.baz2.Gamma
    [java] === Supremo ends ===
buildall:
    [echo] The build has ended successfully.
BUILD SUCCESSFUL
Total time: 313 milliseconds

================================

Does anyone know why I'm having this problem? Am I doing something foolish
in the way I create the FileHandler? Or is this what it appears to be, a
weird Ant/Java compatibility issue?

I'm using jdk 1.60.18.

--
Rhino