Fast loading Java program

Question

The book "Core Java, Volume I" by Horstmann and Cornell gives a hint for writing a Java program that loads quickly. They suggest that explicit references to other classes be eliminated from the main class, then use Class.forName to force the loading of the other classes.
I would like to see if the loading of other classes can be done on demand. Here is the schetch of my idea for instantiating and calling a method.
Class myClassObj = Class.forName("MyClass");
Object myObj = myClassObj.newInstance();
Constructor myConstr = myClassObj.getConstructor(new Class[] {String});
myConstr.invoke??
Method myMethod = myClassObj.getMethod("myMethod",new Class[]{String,int});
myMethod.invoke(myObj,new Obj []{"Julie",23});
Here are my questions:
1. I can use myClassObj.getConstructor to get a specific constructor but how would I invoke it? Does newInstance call a constructor already?
2. How would Invoke a static method?
3. If this approach is feasible, would you recomend it?
Thanks for your help.

Answer 1

1. I can use myClassObj.getConstructor to get a
specific constructor but how would I invoke it? Does
newInstance call a constructor already?The newInstance of Class calls the constructor with no arguments. To create an object using a Constructor instance, use its newInstance method.
2. How would Invoke a static method?The API documentation for the invoke() method of Method tells you that. It says "If the underlying method is static, then the specified obj argument is ignored. It may be null."
3. If this approach is feasible, would you recomend
it?Almost certainly not. If you simply replace explicit references to the class by calls to Class.forName(), you are still going to be loading the same classes at the same time. So I don't see how this would speed up loading. And I definitely wouldn't recommend putting all that reflection code in your program. First of all, it's slower, so you could negate whatever benefits you might have got at loading time, and second, it makes your program hard to write, difficult to maintain, and subject to run-time errors because you don't allow the compiler to check method names and signatures.
But if time to load the program is of much higher importance than any of those other considerations, then give it a try.