Most likely you just need to scroll up from that error.
I just put something in a java file so it wouldn't compile and then tried to run it and got this:
--- exec-maven-plugin:1.2.1:exec (default-cli) @ mavenproject3 ---
Error: Could not find or load main class wshackle.mavenproject3.Test1
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BUILD FAILURE
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Total time: 2.122s
Finished at: Tue Aug 18 21:36:33 EDT 2015
Final Memory: 5M/78M
------------------------------------------------------------------------
Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec (default-cli) on project mavenproject3: 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
The entire error you pasted is really generic and will get printed for almost any error. But if you scrolled up you can see that in my case I have a
BUILD FAILURE. To see what the error was in my case, I would rebuild (Shift F11). This is probably a good idea often when there are run errors.