This error says that you used the wrong spelling of the class name:
Exception in thread "main" java.lang.NoClassDefFoundError: TestConst (wrong name
: Testconst)
It says you typed it as "TestConst" and that you should type it as "Testconst".
It is spelled as "Testconst" in your previous post. The compiler doesn't care about case but the jvm, ie, the "java" command/tool, is very picky about it.