Eclipse Maven Plugin Configuration Problem

Question

I have followed this thread

now when i try to build using maven plugin installed i am getting following error. goal i executed was clean -X install

Unable to locate the Javac Compiler in:
  C:\Program Files\Java\jre6\..\lib\tools.jar
Please ensure you are using JDK 1.4 or above and
not a JRE (the com.sun.tools.javac.Main class is required).
In most cases you can change the location of your Java
installation by setting the JAVA_HOME environment variable.
-> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.0.2:compile (default-compile) on project trojantime: Compilation failure
Unable to locate the Javac Compiler in:
  C:\Program Files\Java\jre6\..\lib\tools.jar
Please ensure you are using JDK 1.4 or above and
not a JRE (the com.sun.tools.javac.Main class is required).
In most cases you can change the location of your Java
installation by setting the JAVA_HOME environment variable.

    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:581)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:324)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:247)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:104)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:427)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:157)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:121)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.apache.maven.plugin.CompilationFailureException: Compilation failure
Unable to locate the Javac Compiler in:
  C:\Program Files\Java\jre6\..\lib\tools.jar
Please ensure you are using JDK 1.4 or above and
not a JRE (the com.sun.tools.javac.Main class is required).
In most cases you can change the location of your Java
installation by setting the JAVA_HOME environment variable.

    at org.apache.maven.plugin.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:516)
    at org.apache.maven.plugin.CompilerMojo.execute(CompilerMojo.java:114)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:105)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:577)
    ... 14 more
[ERROR] 
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

in Installed JRE from preferences it is JRE set and

here is the snapshot of about>installation>configuration>

*** Platform Details:

*** System properties:
awt.toolkit=sun.awt.windows.WToolkit
com.sun.management.jmxremote=
eclipse.application=org.eclipse.ui.ide.workbench
eclipse.commands=-os
win32
-ws
win32
-arch
x86
-showsplash
D:\eclipse VT preconfigured\eclipse\\plugins\org.eclipse.platform_3.3.202.v201002111343\splash.bmp
-launcher
D:\eclipse VT preconfigured\eclipse\eclipse.exe
-name
Eclipse
--launcher.library
D:\eclipse VT preconfigured\eclipse\plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.0.200.v20090519\eclipse_1206.dll
-startup
D:\eclipse VT preconfigured\eclipse\plugins/org.eclipse.equinox.launcher_1.0.201.R35x_v20090715.jar
-showlocation
-product
org.eclipse.epp.package.jee.product
-vm
c:\Program Files\Java\jdk1.6.0_04\jre\bin\client\jvm.dll
eclipse.home.location=file:/D:/eclipse VT preconfigured/eclipse/
eclipse.launcher=D:\eclipse VT preconfigured\eclipse\eclipse.exe
[email protected]/../p2/
eclipse.p2.profile=epp.package.jee
eclipse.product=org.eclipse.epp.package.jee.product
eclipse.startTime=1279882656890
eclipse.vm=c:\Program Files\Java\jdk1.6.0_04\jre\bin\client\jvm.dll
eclipse.vmargs=-Dosgi.requiredJavaVersion=1.5
-Xms40m
-Xmx740m
-Xss4m
-XX:PermSize=128m
-XX:MaxPermSize=128m
-XX:CompileThreshold=5
-XX:MaxGCPauseMillis=10
-XX:MaxHeapFreeRatio=70
-XX:+UseConcMarkSweepGC
-XX:+CMSIncrementalMode
-XX:+CMSIncrementalPacing
-Dcom.sun.management.jmxremote
-Djava.class.path=D:\eclipse VT preconfigured\eclipse\plugins/org.eclipse.equinox.launcher_1.0.201.R35x_v20090715.jar
file.encoding=Cp1252
file.encoding.pkg=sun.io
file.separator=\
java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment
java.awt.printerjob=sun.awt.windows.WPrinterJob
java.class.path=D:\eclipse VT preconfigured\eclipse\plugins/org.eclipse.equinox.launcher_1.0.201.R35x_v20090715.jar
java.class.version=50.0
java.endorsed.dirs=c:\Program Files\Java\jdk1.6.0_04\jre\lib\endorsed
java.ext.dirs=c:\Program Files\Java\jdk1.6.0_04\jre\lib\ext;C:\WINDOWS\Sun\Java\lib\ext
java.home=c:\Program Files\Java\jdk1.6.0_04\jre
java.io.tmpdir=C:\DOCUME~1\argus\LOCALS~1\Temp\
java.library.path=D:\eclipse VT preconfigured\eclipse;.;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;c:/Program Files/Java/jdk1.6.0_04/jre/bin/client;c:/Program Files/Java/jdk1.6.0_04/jre/bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\TortoiseSVN\bin;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\Java\jdk1.6.0_04\bin;C:\Program Files\MySQL\MySQL Server 5.1\bin;C:\Documents and Settings\argus\My Documents\apache-ant-1.7.1-bin\apache-ant-1.7.1\bin;C:\Documents and Settings\argus\My Documents\apache-maven-2.0.10\bin;C:\Documents and Settings\argus\My Documents\groovy-binary-1.7.3\groovy-1.7.3\bin;C:\Documents and Settings\argus\My Documents\patch-2.5.9-7-bin\bin
java.rmi.server.randomIDs=true
java.runtime.name=Java(TM) SE Runtime Environment
java.runtime.version=1.6.0_04-b12
java.specification.name=Java Platform API Specification
java.specification.vendor=Sun Microsystems Inc.
java.specification.version=1.6
java.vendor=Sun Microsystems Inc.
java.vendor.url=http://java.sun.com/
java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport.cgi
java.version=1.6.0_04
java.vm.info=mixed mode
java.vm.name=Java HotSpot(TM) Client VM
java.vm.specification.name=Java Virtual Machine Specification
java.vm.specification.vendor=Sun Microsystems Inc.
java.vm.specification.version=1.0
java.vm.vendor=Sun Microsystems Inc.
java.vm.version=10.0-b19
line.separator=
.
.
.

Answer 1

It appears that Eclipse is still referring to a JRE instead of a JDK. Also, the default runtime in Eclipse (found in the "Installed Runtimes" page of the Preferences dialog) might be a JRE.

I've noticed that this sometimes occurs due to multiple VM configurations being obtained, with the first or the last being applied. You can confirm whether this is the case (in Helios), by going to the About page of Eclipse, and then viewing the Configuration tab in Installation Details. Usually the culprit turns out to be a missing new line in eclipse.ini.