When you start a library the Eclipse Library template provide a class. let's call it Class1. 

If I crate two more classes (classA and classB) and I want to instantiate ClassB into class1 works ok. But If I need to instantiate ClassB into ClassA I got an error: ClassB cannot be resolved to a type.

code example:

1. public class ClassA{
2. PApplet parent;
3.       public ClassA(PApplet myParent)
4.       {
5.             parent = myParent;
6.       }
7.       public void Foo()
8.       {
9.       ClassB cb = new ClassB(); //error -> cannot be resolved to a type.
10.       }
11. }

2. public class ClassB
3. {
4. public ClassB() //empty constructor
5. {
6. 
   
7. }
8.       
9.      public int[] RandomNumbers(int cant)
10.       {
11.             return random numbers
12.       }
13. }
14. 
    

regards

C.