public classe Programa {
    public static void main (String[] args) {
        System.out.println("ola Mundo");
        }
} 

Olá Nogueira,

utilize a palavra chave class ao invés de classe.

error: class, interface, or enum expected

Surgiu novo erro???? referente a versão java... C:\java.codigo>java Programa Error: A JNI error has occurred, please check your installation and try again Exception in thread "main" java.lang.UnsupportedClassVersionError: Programa has been compiled by a more recent version of the Java Runtime (class file version 56.0), this version of the Java Runtime only recognizes class file versions up to 52.0 at java.lang.ClassLoader.defineClass1(Native Method) 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$100(Unknown Source) at java.net.URLClassLoader$1.run(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 sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

C:\java.codigo>