How to get return value of invoked method?

I'm trying to achieve some sort of reflection in java. I have:

class P {
  double t(double x) {
    return x*x;
  }

  double f(String name, double x) {
    Method method;
    Class<?> enclosingClass = getClass().getEnclosingClass();
     if (enclosingClass != null) {
        method = enclosingClass.getDeclaredMethod(name, x);
        try {
          method.invoke(this, x);
        } catch (Exception e) {
          e.printStackTrace();
        }

    }
}

class o extends P {
  double c() { 
    return f("t", 5);
  }
}

How do I get value from new o().c()?