SOAPUI API Problem when trying to execute conditional Goto

Hi everyone, I'm actually running my soapui test using JUNIT.

Everything works fine when I'm running my test in soapui but when I call it from my Junit test, I get an error when executing a conditional goto instruction and get the following message :

10:26:58,875 INFO  [SoapUITestCaseRunner] running step [Conditional Goto]
10:26:58,906 ERROR [AbstractTestRunner] Exception during Test Execution
java.lang.UnsupportedClassVersionError: Bad version number in .class file
 at java.lang.ClassLoader.defineClass1(Native Method)
 at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
 at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
 at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
 at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
 at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
 at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
 at com.eviware.soapui.impl.rest.support.MediaTypeHandlerRegistry.<clinit>(MediaTypeHandlerRegistry.java:30)
 at com.eviware.soapui.impl.wsdl.submit.transports.http.BaseHttpResponse.getContentAsXml(BaseHttpResponse.java:416)
 at com.eviware.soapui.impl.wsdl.teststeps.WsdlGotoTestStep$GotoCondition.evaluate(WsdlGotoTestStep.java:270)
 at com.eviware.soapui.impl.wsdl.teststeps.WsdlGotoTestStep.runConditions(WsdlGotoTestStep.java:149)
 at com.eviware.soapui.impl.wsdl.teststeps.WsdlGotoTestStep.run(WsdlGotoTestStep.java:123)
 at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCaseRunner.runTestStep(WsdlTestCaseRunner.java:207)
 at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCaseRunner.internalRun(WsdlTestCaseRunner.java:138)
 at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCaseRunner.internalRun(WsdlTestCaseRunner.java:39)
 at com.eviware.soapui.impl.wsdl.support.AbstractTestRunner.run(AbstractTestRunner.java:135)
 at com.eviware.soapui.impl.wsdl.support.AbstractTestRunner.start(AbstractTestRunner.java:77)
 at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCase.run(WsdlTestCase.java:599)
 at com.eviware.soapui.tools.SoapUITestCaseRunner.runTestCase(SoapUITestCaseRunner.java:554)
 at com.eviware.soapui.tools.SoapUITestCaseRunner.runRunner(SoapUITestCaseRunner.java:379)
 at com.eviware.soapui.tools.AbstractSoapUIRunner.run(AbstractSoapUIRunner.java:144)
 at fr.mi.siv.simu.test.auto.TestAutoSim.test0401ImVn(TestAutoSim.java:91)
 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:585)
 at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59)
 at org.junit.internal.runners.MethodRoadie.runTestMethod(MethodRoadie.java:98)
 at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:79)
 at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:87)
 at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:77)
 at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
 at org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod(JUnit4ClassRunner.java:88)
 at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
 at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
 at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
 at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
 at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
10:26:58,906 INFO  [SoapUITestCaseRunner] Finished running soapUI testcase [test], time taken: 15381ms, status: FAILED
10:26:58,906 INFO  [SoapUITestCaseRunner] TestCase [test] finished with status [FAILED] in 15381ms


java.lang.Exception: TestCase [test] failed without assertions

 at com.eviware.soapui.tools.SoapUITestCaseRunner.throwFailureException(SoapUITestCaseRunner.java:492)
 at com.eviware.soapui.tools.SoapUITestCaseRunner.runRunner(SoapUITestCaseRunner.java:417)
 at com.eviware.soapui.tools.AbstractSoapUIRunner.run(AbstractSoapUIRunner.java:144)
 at fr.mi.siv.simu.test.auto.TestAutoSim.test0401ImVn(TestAutoSim.java:91)
 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:585)
 at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59)
 at org.junit.internal.runners.MethodRoadie.runTestMethod(MethodRoadie.java:98)
 at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:79)
 at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:87)
 at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:77)
 at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
 at org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod(JUnit4ClassRunner.java:88)
 at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
 at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
 at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
 at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
 at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Does someone have an idea of what it means ? or maybe that functionnality doesn't work in the API ?

Thank you