What is RFC?

RFC stands for Response For Class. RFC measures the complexity of the class in terms of method calls.

For each class, it counts:

+1 for each method
+1 for each call of a distinct method (note that getters and setters are not considered as methods)

Example:

public class ClassA 
{
  private ClassB classB = new ClassB();        // call (constructor of class B) => +1
  public void doSomething(){                   // method declaration => +1
    System.out.println ( "doSomething");       // call (System.out.println) => +1
  }
  public void doSomethingBasedOnClassB(){      // method declaration => +1
    System.out.println (classB.toString());    // call (System.out.println) => 0 because already counted on line 5 + call (toString) => +1
  }
}
 
// default constructor of ClassA => +1
// RFC = 6

How to Hunt for Bad RFC?

Add the Response for class widget (was Chidamber & Kemerer widget for Sonar versions prior to 3.3) on your dashboard:

Sonar > RFC - Checking Coupling > rfc_widget.png

and drill down.