Eclipse Maven project: Unable to locate the Javac Compiler

[Dave Alvarado]

Hi,

I'm using Eclipse Indigo on Win XP, Maven 3.0.3 and I have just built a Maven-GWT project using GWT 2.4 and the gwt-maven-plugin. Despite the fact that I have pointed my Eclipse JDK to what I have installed -- http://screencast.com/t/7TYkFh8rcObL, I'm still getting this error when I right click on my project and select the "Maven Install" option ...

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building GWT Maven Archetype 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- gwt-maven-plugin:2.4.0:i18n (default) @ samplemavengwt ---
[INFO] 
[INFO] --- gwt-maven-plugin:2.4.0:generateAsync (default) @ samplemavengwt ---
[INFO] 
[INFO] --- maven-resources-plugin:2.4.3:resources (default-resources) @ samplemavengwt ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 3 resources
[INFO] 
[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) @ samplemavengwt ---
[INFO] Compiling 1 source file to C:\Documents and Settings\E18538\workspace\samplemavengwt\target\samplemavengwt-1.0-SNAPSHOT\WEB-INF\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] 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.
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.328s
[INFO] Finished at: Thu Nov 03 10:31:40 CDT 2011
[INFO] Final Memory: 5M/15M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project samplemavengwt: Compilation failure
[ERROR] Unable to locate the Javac Compiler in:
[ERROR] C:\Program Files\Java\jre6\..\lib\tools.jar
[ERROR] Please ensure you are using JDK 1.4 or above and
[ERROR] not a JRE (the com.sun.tools.javac.Main class is required).
[ERROR] In most cases you can change the location of your Java
[ERROR] installation by setting the JAVA_HOME environment variable.
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[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

I verified through the Windows start menu -> Run, "cmd" window that %JAVA_HOME% is set properly. What other settings do I need to adjust to eliminate the above error?

- Dave

[Muhammad Saifuddin]

as the errors already point out the solution.

can you paste the path right here, you set under JAVA_HOME variable.

or make sure you did right Setting Java home And Path

[Dave Alvarado]

Sure. The path is set to

C:\Program Files\Java\jdk1.6.0_27

You can see it here -- http://screencast.com/t/ON65FsgGp . I verified this path exists by going to the Start Menu, selecting "Run", entering "cmd" and then doing "cd %JAVA_HOME%" at the command prompt, which successfully changes the current working directory.

- Dave

[Muhammad Saifuddin]

Opps!! I missed your first post picture.

you should select the jre instead of jdk under Installed JREs option and check the compiler option in same java tree.
and verify the right compiler within JDK Compliance.

[Jesper de Jong]

Dave Alvarado wrote:The path is set to

C:\Program Files\Java\jdk1.6.0_27

You should put the bin directory of your JDK installation directory in the PATH; not the JDK installation directory itself. So this must be included in your PATH:

C:\Program Files\Java\jdk1.6.0_27\bin

Note: I'm talking about the PATH environment variable, not the JAVA_HOME environment variable.

[Dave Alvarado]

Mohammed,

I tried switching to the JRE you recommended. Also, my compiler is set to 1.6 (http://screencast.com/t/kKGB6b8IEkPW), but I got the same result as before, right-clicking on my project, seleting Run As -> Maven Install. But why would I move away from a Java installation that had javac? The error is complaining about not being able to find javac, so how do I tell the Maven-Eclipse plugin where to find it?

Jasper,

If you looked at the screen shot I sent, the thing I cut and pasted was actually my JAVA_HOME. I mistyped "path" in the previous post. My environment variables %PATH% is set to

C:\Oracle11g\11.2.0\client_1\bin;c:\tibco\tibrv\8.2\bin;C:\Program Files\RSA SecurID Token Common;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SystemRoot%\system32\nls;%SystemRoot%\system32\nls\ENGLISH;C:\Program Files\Novell\ZENworks\;C:\Program Files\Hummingbird\Connectivity\9.00\NFSClient;C:\Program Files\ZANTAZ\EAS Client\;C:\Program Files\Rational\common;C:\Program Files\Rational\ClearCase\bin;c:\apache-ant-1.8.2\bin;C:\Program Files\Java\jdk1.6.0_27\bin;C:\PROGRA~1\IBM\SQLLIB\BIN;C:\PROGRA~1\IBM\SQLLIB\FUNCTION;C:\Program Files\Microsoft SQL Server\90\Tools\binn\;%MAVEN_HOME%\bin;%M2_HOME%\bin;C:\Program Files\Git\cmd;C:\Program Files\TortoiseGit\bin

What is the relationship between the %PATH% and %JAVA_HOME% env.vars and what the Maven Eclipse plugin uses to execute Maven commands? - Dave

[Muhammad Saifuddin]

Its hard to say why eclipse pointing jre instead of jdk for locating tools.jar file, even after applied all settings correctly.

I suggest you to hit the same link again "Setting Java home And Path" and follow these steps again, specially point No. 6 and 7.

What is the relationship between the %PATH% and %JAVA_HOME% env.vars and what the Maven Eclipse plugin uses to execute Maven commands?

a little down scroll in the same link will show you the details regarding both variables.

[Peter Johnson]

Did you add the -vm option to eclipse.ini? See this discussion:
https://coderanch.com/t/488574/vc/Eclipse-running-JRE-but-JDK