Maven unable to locate Javac Compiler - Unable to locate the Javac Compiler in:

Question

When I try to make maven-install on my gwt-maven Projekt i get this Error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project MyProject: Compilation failure
[ERROR] Unable to locate the Javac Compiler in:
[ERROR] C:\Development\java jre7\..\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

But JAVA_HOME is set. When I run cmd "echo %JAVA_HOME%" it says C:\Development\jdk7 and this is correct. Dont know why he is searching for C:\Development\java jre7.....

Answer 1

Looks like your JAVA_HOME might be pointing to a JRE instead if a JDK?

C:\Development\java jre7\..\lib\tools.jar

Do you have a JDK installed? If so, change your JAVA_HOME to point to the JDK instead. If not, download the JDK first and then set JAVA_HOME.

Update

Since you're running from inside Eclipse your answer is on SO - you need to tell Eclipse to use the JDK and not the JRE.

Answer 2

For eclipse user:
Way 1:

1. Right Click on Eclipse project -> Go to Properties
2. Java Build Path -> Libraries
3. Click on JRE System Library -> Click Edit button at right side -> Click on Installed JRE
4. Edit JRE -> Set JRE Home = JAVA_HOME (In my case JAVA_HOME is C:\Program Files\Java\jdk1.7.0_45)

Way 2:

1. Go to Window -> Preferences -> Java -> installed JREs
2. Edit the existing JRE location as: Set JRE Home = JAVA_HOME or JAVA_HOME\jre (In my case the path was C:\Program Files\Java\jdk1.7.0_45 OR C:\Program Files\Java\jdk1.7.0_45\jre)
3. Click Finish and OK button

Way 3:

1. Go to Window -> Preferences -> Java -> installed JREs
2. Select the JRE you are using
3. Press Edit -> Add External JARs...
4. Browse to Java\jdk1.7.0_45\lib and select tools.jar and Press Enter
5. Click Finish and OK button