JComboBox is a
generic type - it takes type parameters. You're using it with type arguments in some places, but not in other places. For example, you're creating number of JComboBox<String> objects, but when you declare the array private JComboBox[] jcb you're not specifying type parameters.
A generic type without using type parameters is called a raw type. Raw types exist in
Java for backward compatibility - generics were added in Java version 5.0, and to keep Java backwards compatible with older versions it's still possible to use raw types.
You should however not use raw types, that's why you get this warning.
There is, however, one more complication in your case. You cannot do
private JComboBox<String>[] jcb because Java
does not allow you to create an array of a parameterized type. The reason for that is complicated and has to do with how arrays and generics work in Java.
The best solution is to use a List instead of an array: