code: @Override
      public void visitClassContext(ClassContext classContext) {
          try {
              JavaClass cls = classContext.getJavaClass();
              if (cls.isAbstract()) {
                  interfaceMethods = collectInterfaceMethods(cls);
                  super.visitClassContext(classContext);
              }
          } catch (ClassNotFoundException cnfe) {
              bugReporter.reportMissingClass(cnfe);
          } finally {
              interfaceMethods = null;
          }
      }
docs: overrides the visitor to check for abstract classes.
  
  @param classContext
  the context object that holds the JavaClass being parsed