java动态类加载

Question

When loading the class, using method forName() , any static initializers in the class are executed. Can I prevent this ?

try {
        Class.forName("MYClass");
    } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

MyClass

class MyClass{

static String TEST="MYCLASS";
static SomeClass sm=new SomeClass();
}

I found in doc that there is a overloaded version of Class.forName() ie

public static Class<?> forName(String name,
                           boolean initialize,
                           ClassLoader loader)
                    throws ClassNotFoundException

What is initialize parameter ?

Answer 1

This is how Java creates objects, so no. One way would be to lazy load the instances at some other time.

This would imply you would have to remove the static reference.

eg

public SomeClass getSomeClass() {
   if (sm == null) {
      return new SomeClass();
   }

   return sm;

}

Answer 2

If you dont want to execute static initialization try class literal instead of Class.forName

class A1{
    static{
        System.out.println("static block from A1");
    }
}

class B1{
    public static void main(String[] args) throws ClassNotFoundException {
//      Class.forName("A1");//this will invoke static initialization
        Class c=A1.class;//this will not invoke static initialization
    }
}