I've just tried this new version of closure compiler and I get the following error:
Error: Command failed: Exception in thread "main" java.lang.UnsupportedClassVersionError: com/google/javascript/jscomp/CommandLineRunner : 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)
>> FAILED to run command for target: targetName