老師，項目運行時報錯：

java.lang.UnsupportedClassVersionError:?com/parser/test/ParseTest?:?Unsupported?major.minor?version?51.0
	at?java.lang.ClassLoader.defineClass1(Native?Method)
	at?java.lang.ClassLoader.defineClassCond(Unknown?Source)
	at?java.lang.ClassLoader.defineClass(Unknown?Source)
	at?java.security.SecureClassLoader.defineClass(Unknown?Source)
	at?java.net.URLClassLoader.defineClass(Unknown?Source)
	at?java.net.URLClassLoader.access$000(Unknown?Source)
	at?java.net.URLClassLoader$1.run(Unknown?Source)
	at?java.security.AccessController.doPrivileged(Native?Method)
	at?java.net.URLClassLoader.findClass(Unknown?Source)
	at?java.lang.ClassLoader.loadClass(Unknown?Source)
	at?sun.misc.Launcher$AppClassLoader.loadClass(Unknown?Source)
	at?java.lang.ClassLoader.loadClass(Unknown?Source)
	at?org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClass(RemoteTestRunner.java:693)
	at?org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClasses(RemoteTestRunner.java:429)
	at?org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)
	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)

怎么一回事？