NetBeans - JComboBox warning - missing type arguments for generic class JComboBox<E>

Question

I am using NetBeans IDE 7.1.2. When I compile my application I get the following warning:

warning: [rawtypes] found raw type: JComboBox city = new javax.swing.JComboBox(); missing type arguments for generic class JComboBox where E is a type-variable: E extends Object declared in class JComboBox

So, I guess I have to declare the JComboBox as:

JComboBox<String> city = new JComboBox<String>();

But how do I do this in NetBeans, using the Matisse (Swing GUI Builder)? Please help.

Contingence

Answer 1

In Netbeans 7.2 you can click on Code section for JComboBox, and then write type into "Type Parameters", in your case: <String>.

Snob

This helped, just one small improvement to clarify how to get to the code section: right-click the JComboBox, choose Properties, select the Code section (at the top of the properties window). Type Parameters is close to the top. – Yearlong

@chr and remember to write the type parameter including the angle brackets. – Gunas

Answer 2

Java 7 introduced generics to the JComboBox. One solution to your problem would be to ust Java 6.

I'd bet the latest version of Netbeans (7.2) will have a solution for this (although I'm not positive).

Otherwise, if I remember right, you can view the code generated by Netbeans. If so, you may be able to add the generic arguement yourself. It's been many months since I tinkered with Netbeans though...

Also, if the Netbeans allows you to, you can add the @SupressesWarnings annotation above the JComboBox declaration (or even above the class declaration, although that changes it's scope). It would be something like this:

@SuppressWarnings("rawtypes")
JComboBox city = new JComboBox();

There are lots of options, but Netbeans may hold you back from implementing some of them.

Ratite

Nick I tried to change the code to: city = new javax.swing.JComboBox<String>(); (NetBeans does not allow me to change the declaration variables therefore my city is defined as private javax.swing.JComboBox city;). When I did this I get the following warning: redundant type arguments in new expression (use diamond operator instead). – Contingence

I'm not sure you'll be able to get around the warning then without downgrading your Java version or updating your Netbeans IDE. Fortunately, it's just a warning so it won't affect your actual code. If it bothers you, you can try adding this line above your declaration: @SuppressWarnings("rawtypes") I'll add this to the answer as well. I don't know of a way to turn compiler warnings off in Netbeans - someone else may know. – Ratite

Thank you very much Nick. At least now I know that I am not doing anything wrong as per coding. I hope this is fixed in the v7.2, I haven't tried it yet, waiting for oracle to release it with JDK. – Contingence