For some reason, every time i try to run an application by using: java HelloWorld, it tells me this message...

Exception in thread "main" java.lang.UnsupportedClassVersionError: HelloWorld

What might be the problem and how can I fix it?

Oh, and when I try: java HelloWorldApp, it gives me this message:

Exception in thread "main" java.lang.UnsupportedClassVersionError: HelloWorldApp (Unsupported major.minor version 49.0)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java :539)
at java.security.SecureClassLoader.defineClass(Secure ClassLoader.java:123)
at java.net.URLClassLoader.defineClass(URLClassLoader .java:251)
at java.net.URLClassLoader.access$100(URLClassLoader. java:55)
at java.net.URLClassLoader$1.run(URLClassLoader.java: 194)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:187)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 89)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:274)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 35)
at java.lang.ClassLoader.loadClassInternal(ClassLoade r.java:302)