java version problem

[mche...@gmail.com]

Hi All
I am using netbeans, only one version of java is installed. Why i am having this error:

cd /root/NetBeansProjects/WaiOnBackend; JAVA_HOME=/root/Downloads/jdk1.8.0_51 /usr/local/netbeans-8.0.2/java/maven/bin/mvn "-Dexec.args=-classpath %classpath CheckoutJobTest" -Dexec.executable=java -Dexec.classpathScope=test org.codehaus.mojo:exec-maven-plugin:1.2.1:exec
Running NetBeans Compile On Save execution. Phase execution is skipped and output directories of dependency projects (with Compile on Save turned on) will be used instead of their jar artifacts.
Scanning for projects...

------------------------------------------------------------------------
Building WaiOnBackend 20150806
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--- exec-maven-plugin:1.2.1:exec (default-cli) @ backend ---
Exception in thread "main" java.lang.UnsupportedClassVersionError: CheckoutJobTest : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
------------------------------------------------------------------------
BUILD FAILURE
------------------------------------------------------------------------
Total time: 1.606s
Finished at: Wed Oct 14 20:37:21 CST 2015
Final Memory: 8M/483M
------------------------------------------------------------------------
Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec (default-cli) on project backend: Command execution failed. Process exited with an error: 1 (Exit value: 1) -> [Help 1]

To see the full stack trace of the errors, re-run Maven with the -e switch.
Re-run Maven using the -X switch to enable full debug logging.

For more information about the errors and possible solutions, please read the following articles:
[Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException


thanks
from Peter