In this case, the function expects an instance of Class, which is a recursive representation of a class. However, you are sending a class itself, which is not an instance. Your Processing code would need to build a Class object and pass that.

You should change the method to

1. public boolean setActiveTool(Tool tool) {
2.       for(Tool t : tools) {
3.             if(t.getClass() == tool.getClass()) {
4.                   activeTool = t;
5.                   return true;
6.             }
7.       }
8.       return false;
9. }

Remember a Tool reference can refer to an object of type Tool OR an object of any class that inherits from Tool, so in this case it can be a PenTool

So tools is a collection of Tool or Tool sub-class objects.

You also need to clarify the reason for having tools is it

1. to make sure that tool is of type Tool or a sub-class
2. to ensure that tool is the same class as one of the existing objects in tools
3. to make sure the object tool is the same object as one of those in tools

because it will make a difference to the code inside this method. Currently you are doing (2)

HTH

thanks, i made the changes.

this works:

1.   PenTool pt = new PenTool();
2.   toolHandler.setActiveTool(pt);

but this doen't,

1.   toolHandler.setActiveTool(PenTool);

i still get "cannot find anything named "PenTool""

That is because you have not clearly stated the problem  which is why I asked about the role of tools.

Try this

1. public boolean setActiveTool(Class c) {
2.       for(Tool t : tools) {
3.             if(t.getClass() == c) {
4.                   activeTool = t;
5.                   return true;
6.             }
7.       }
8.       return false;
9. }

and

1. toolHandler.setActiveTool(PenTool.getClass());

It will find the first object in tools that is of type PenClass and make that active

thanks.

about:

1. PenTool.getClass()

that returns the class,

but what is PenTool itself then?

PenTool is the name of a class and thats it.

1. 
     toolHandler.setActiveTool(PenTool);

i still get "cannot find anything named "PenTool""

Try to put "public" before your class definitions!

This works:

Or if you reall need to use classes:

thanks, last one was really learnfull.