mvn test exception | jetty-server | UnsupportedClassVersion

Question

Please help me identify what is actually wrong with mvn test.

nik@ubuntu:myproj$ mvn test
[INFO] Scanning for projects...
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for com.myproj:jar:1.0.0-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-surefire-plugin is missing. @ line 83, column 15
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING] 
[INFO] Inspecting build with total of 1 modules...
[INFO] Installing Nexus Staging features:
[INFO]   ... total of 1 executions of maven-deploy-plugin replaced with nexus-staging-maven-plugin
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building myproj 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.3:resources (default-resources) @ myproj ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 32 resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.0:compile (default-compile) @ myproj ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:2.3:testResources (default-testResources) @ myproj ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 10 resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.0:testCompile (default-testCompile) @ myproj ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 15 source files to /home/nik/myproj/target/test-classes
[WARNING] Note: Some input files use unchecked or unsafe operations.
[WARNING] Note: Recompile with -Xlint:unchecked for details.
[INFO] 
[INFO] --- maven-surefire-plugin:2.10:test (default-test) @ myproj ---
[INFO] Surefire report directory: /home/nik/myproj/target/surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
org.apache.maven.surefire.util.SurefireReflectionException:                        java.lang.reflect.InvocationTargetException; nested exception is         java.lang.reflect.InvocationTargetException: null
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:164)
at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:110)
at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:175)
at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcessWhenForked(SurefireStarter.java:107)
at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:68)
Caused by: java.lang.UnsupportedClassVersionError: org/eclipse/jetty/server/Handler : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2436)
at java.lang.Class.getMethod0(Class.java:2679)
at java.lang.Class.getMethod(Class.java:1605)
at org.apache.maven.surefire.util.ReflectionUtils.tryGetMethod(ReflectionUtils.java:57)
at org.apache.maven.surefire.common.junit3.JUnit3TestChecker.isSuiteOnly(JUnit3TestChecker.java:65)
at org.apache.maven.surefire.common.junit3.JUnit3TestChecker.isValidJUnit3Test(JUnit3TestChecker.java:60)
at org.apache.maven.surefire.common.junit3.JUnit3TestChecker.accept(JUnit3TestChecker.java:55)
at org.apache.maven.surefire.common.junit4.JUnit4TestChecker.accept(JUnit4TestChecker.java:52)
at org.apache.maven.surefire.util.DefaultDirectoryScanner.locateTestClasses(DefaultDirectoryScanner.java:80)
at org.apache.maven.surefire.junit4.JUnit4Provider.scanClassPath(JUnit4Provider.java:174)
at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:83)
... 9 more

Results :

Tests run: 0, Failures: 0, Errors: 0, Skipped: 0

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 14.101s
[INFO] Finished at: Fri Feb 28 19:43:56 PST 2014
[INFO] Final Memory: 21M/59M
[INFO] ------------------------------------------------------------------------

Additional info:

nik@ubuntu:myproj$ java -version
java version "1.6.0_45"
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)

nik@ubuntu:myproj$ javac -version
javac 1.6.0_45

pom.xml is huge. So pasting only the snippet relevant to surefire-plugin and jetty-server.

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
      <configuration>
     </configuration>
  </plugin>


<dependency>
  <groupId>org.eclipse.jetty</groupId>
  <artifactId>jetty-server</artifactId>
  <version>9.1.0.M0</version>
  <scope>test</scope>
</dependency>

Answer 1

The interesting part of the error is this:

Caused by: java.lang.UnsupportedClassVersionError: org/eclipse/jetty/server/Handler : Unsupported major.minor version 51.0

This means you are using a jar containing a class file (in this case org.eclipse.jetty.server.Handler) that was compiled for Java 7. As your java -version output has shown, you are using Java 1.6.0_45. You should upgrade your java[c] to 1.7.