The java program (i.e., the java virtual machine) expects its argument to be a fully qualified class name.

      java options fully_qualified_class_name
   

If the class is not in a package (i.e., no package statement), the fully qualified name is just the class name.

If the class is in a package, the fully qualified name includes the package and the class name.

So in the example, the fully qualified name is

bank.Bank

Note that unlike the argument to the javac command, the argument to java is not the relative or absolute path to the .class file!