Howto instantiate a dynamic SUBclass with parametized Constructor

Question

Hi again folks; whoever followed from previous thread; thanks.
As DrClap said, this is trivial, but so far I have problems. The key question is in the red comments.
package ezDBpkg;
import java.lang.reflect.*;
import java.sql.*;
public class TestDBC implements DbContrlr {
  private DbContStorage pMyStorage = new DbContStorage();
  Constructor ceo = buildGlobalEOconstructor();
  private Constructor buildGlobalEOconstructor(){
    Class[] params = new Class[2];
    params[0] = DbContrlr.class;
    params[1] = String.class;
    Constructor co=null;
    try{
      Class cl = Class.forName("EO");
      co = cl.getConstructor(params);
    }catch (ClassNotFoundException cnfEX) {cnfEX.printStackTrace();
    }catch (NoSuchMethodException nsmEX) {nsmEX.printStackTrace();
    return co;
//The key question is in the following method:
//How do I instantiate a new class whose name is inside the newDynamicEoSubclass string,
//which is always a subclass of my EO class.
  public void manufactureDynamicEO(String newDynamicEoSubclass, String id){
    EO eo=null;
    try{
      eo = ceo.newInstance(new Object[] {this,id});  //this line needs to be corrected to do the trick.
    }catch (InvocationTargetException itEX) {itEX.printStackTrace();
    }catch (IllegalAccessException iaEX) {iaEX.printStackTrace();
    }catch (InstantiationException iEX) {iEX.printStackTrace();
    registerEO((EO)eo);
  public void registerEO(EO eo){
    pMyStorage.mStoreEo(eo);
}Thank you all much;
-nat

Answer 1

Ok, how about this:
public class ClassAController {
public static final ClassA instantiateClassAobject(String className) {
ClassA result = null;
Class theClass = Class.forName(className); // catch exceptions
// Make sure that the class is a subclass of ClassA
if (ClassA.class.isAssignableFrom(theClass)) {
// use newInstance for default constructor, otherwise use
// theClass.getConstructor(Class[]) to get the one you want
Object obj = theClass.newInstance(); // catch exceptions
// add obj into my library of ClassA objects
result = (ClassA) obj; // The type's assignable so this cast is OK
} // endif
return result;
} // instantiateClassAobject()
This assumes that the other developer using your package actually calls instantiateClassAobject() rather than invoking his own constructor.
Wouldn't it be better to simply add some code into the default constructor of ClassA?
If you declare ClassA like this:
public class ClassA {
public ClassA() {
super();
// add this into my library of ClassA objects...
Because ClassA has only the default constructor, you know that it will be invoked by everything that is an instance of ClassA or any of its subclasses. The invocation may be implicit, but it occurs.