java.lang.UnsupportedClassVersionError Unsupported major.minor version 51.0

Question

I am trying to build an application, but it gives some error. My JDK version is given below:

java version "1.6.0_30"

Java(TM) SE Runtime Environment (build 1.6.0_30-b12)

Java HotSpot(TM) Client VM (build 20.5-b03, mixed mode, sharing)

Here is my Error Log:

Buildfile: build.xml

compile:

     [echo] Compiling the service....

     [echo]   ...mkdir for classes first....

     [echo]   ...java classes next....

     [echo]   ...mkdir for generated code next....

     [echo]  ...generate stubs/skeletons next....

[wscompile] command line: wscompile -d /home/vivekray/program/MTrans/WEB-INF/classes -features:wsi,documentliteral -gen:server -keep -model /home/vivekray/program/MTrans/WEB-INF/model.gz -verbose -Xprintstacktrace /home/vivekray/program/MTrans/src/config.xml -classpath /home/vivekray/program/MTrans/WEB-INF:/home/vivekray/program/MTrans/WEB-INF/classes:/home/vivekray/program/MTrans/lib/log4j-1.2.16.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/mail.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/activation.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/jaxp-api.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/dom.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/sax.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/xalan.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/xercesImpl.jar:/home/vivekray/jwsdp-2.0/jaxrpc/lib/jaxrpc-api.jar:/home/vivekray/jwsdp-2.0/jaxrpc/lib/jaxrpc-spi.jar:/home/vivekray/jwsdp-2.0/jaxrpc/lib/jaxrpc-impl.jar:/home/vivekray/jwsdp-2.0/saaj/lib/saaj-api.jar:/home/vivekray/jwsdp-2.0/saaj/lib/saaj-impl.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/relaxngDatatype.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/xsdlib.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/jax-qname.jar:/home/vivekray/jwsdp-2.0/apache-ant/lib/ant.jar:/home/vivekray/jwsdp-2.0/fastinfoset/lib/FastInfoset.jar:/home/vivekray/Softwares/apache-tomcat-7.0.27/lib/servlet-api.jar

[wscompile] [creating model: mtransservice]

[wscompile] [creating service: Mtransservice]

BUILD FAILED

java.lang.UnsupportedClassVersionError: in/cdac/mobile/computing/mtrans/MtransService : 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 org.apache.tools.ant.AntClassLoader.defineClassFromData(AntClassLoader.java:1146)

    at org.apache.tools.ant.AntClassLoader.getClassFromStream(AntClassLoader.java:1324)

    at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1388)

    at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1341)

    at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:1088)

    at java.lang.ClassLoader.loadClass(ClassLoader.java:295)

    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

    at java.lang.Class.forName0(Native Method)

    at java.lang.Class.forName(Class.java:247)

    at com.sun.xml.rpc.processor.modeler.rmi.RmiUtils.getLoadableClassName(RmiUtils.java:78)

    at com.sun.xml.rpc.processor.modeler.rmi.RmiUtils.getRealName(RmiUtils.java:54)

    at com.sun.xml.rpc.processor.modeler.rmi.RmiModeler.modelPort(RmiModeler.java:676)

    at com.sun.xml.rpc.processor.modeler.rmi.RmiModeler.buildLiteralModel(RmiModeler.java:603)

    at com.sun.xml.rpc.processor.modeler.rmi.RmiModeler.buildModel(RmiModeler.java:457)

    at com.sun.xml.rpc.processor.config.ModelInfo.buildModel(ModelInfo.java:88)

    at com.sun.xml.rpc.processor.Processor.runModeler(Processor.java:63)

    at com.sun.xml.rpc.tools.wscompile.CompileTool.run(CompileTool.java:714)

    at com.sun.xml.rpc.util.ToolBase.run(ToolBase.java:43)

    at com.sun.xml.rpc.tools.ant.Wscompile.execute(Wscompile.java:746)

    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)

    at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)

    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

    at java.lang.reflect.Method.invoke(Method.java:597)

    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)

    at org.apache.tools.ant.Task.perform(Task.java:348)

    at org.apache.tools.ant.Target.execute(Target.java:357)

    at org.apache.tools.ant.Target.performTasks(Target.java:385)

    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)

    at org.apache.tools.ant.Project.executeTarget(Project.java:1306)

    at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)

    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)

    at org.apache.tools.ant.Main.runBuild(Main.java:758)

    at org.apache.tools.ant.Main.startAnt(Main.java:217)

    at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)

    at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)

Total time: 1 second

Answer 1

java.lang.UnsupportedClassVersionError happens because of a higher JDK during compile time and lower JDK during runtime.

Here's the list of versions:

Java SE 9 = 53,

Java SE 8 = 52,

Java SE 7 = 51,

Java SE 6.0 = 50,

Java SE 5.0 = 49,

JDK 1.4 = 48,

JDK 1.3 = 47,

JDK 1.2 = 46,

JDK 1.1 = 45