Re: Class.newInstance() Fails with InstantiationException.

Bill Winspur Tue, 05 Feb 2002 03:12:18 -0800

The echoing port never gets instantiated, the attempt to instantiate, by invoking Class.newInstance(), throws an InstantiationException. However, if you are asking what is the function of EchoingPort? ... it is a test stub for for the session side of an http tunneling package to support applet/client access to ejb's via http.

The relevant code follows:--------------------------------------------

/**
* Instantiates the session port if not yet done
*/
private void instantiateIt(String className) throws Exception {

    Class hj = null;
    try {
      hj = Class.forName(className);
      System.out.println(
       "class: " + hj +
       "\n. isInterface: " + hj.isInterface() +
       "\n. isArray: "     + hj.isArray() +
       "\n. isPrimitive: " + hj.isPrimitive() +
       "\n. isAbstract: " + Modifier.isAbstract(hj.getModifiers()) +
       "\n. isFinal: "     + Modifier.isFinal(hj.getModifiers()) +
       "\n. isNative: "    + Modifier.isNative(hj.getModifiers()) +
       "\n. isPrivate: "   + Modifier.isPrivate(hj.getModifiers()) +
       "\n. isProtected: " + Modifier.isProtected(hj.getModifiers()) +
       "\n. isPublic: "    + Modifier.isPublic(hj.getModifiers()) +
       "\n. isStatic: "    + Modifier.isStatic(hj.getModifiers()) +
       "\n. isStrict: "    + Modifier.isStrict(hj.getModifiers()) +
       "\n. isStrict: "    + Modifier.isStrict(hj.getModifiers()) +
       "\n. isTransient: " + Modifier.isTransient(hj.getModifiers()) +
       "\n. isVolatile: " + Modifier.isVolatile(hj.getModifiers())
      );
      try {
        Object oj = hj.newInstance();
        trace("obj: "+ oj);
        trace("Instantiated: " + hj);
      } catch (InstantiationException e) {
        throw new Exception(
                "Cant instantiate a session object: " + e);
      } catch (IllegalAccessException e) {
        throw new Exception(
                "Cant instantiate a session object" + e);
      }
    } catch (Exception ex) {
      throw new Exception(
        "Failed to instantiate className: " + className +
        "\n" + ex.toString() );
    }
}

private void trace(String s) { System.out.println(s); }

The console log produced by the above code is as follows -----------------

class: class com.wynnon.appletChannel.test.EchoingPort
. isInterface: false
. isArray: false
. isPrimitive: false
. isAbstract: false
. isFinal: false
. isNative: false
. isPrivate: false
. isProtected: false
. isPublic: true
. isStatic: false
. isStrict: false
. isStrict: false
. isTransient: false
. isVolatile: false
Failed to instantiate className: com.wynnon.appletChannel.test.EchoingPort
javax.servlet.ServletException: Cant instantiate a session object: java.lang.InstantiationException: com.wynnon.appletChannel.test.EchoingPort

----- Original Message -----

From: menonv

To: Orion-Interest

Sent: Tuesday, February 05, 2002 1:38 AM

Subject: RE: Class.newInstance() Fails with InstantiationException.

What exactly does it do when it gets instantiated?

-----Original Message-----
From: Bill Winspur [mailto:[EMAIL PROTECTED]]
Sent: Monday, February 04, 2002 9:47 PM
To: Orion-Interest
Subject: Class.newInstance() Fails with InstantiationException.

I have a servlet that would instantiate an object, if everything worked. Unfortunately, it fails with the following exception from the Class.newInstance() method:

java.lang.InstantiationException: com.wynnon.appletChannel.test.EchoingPort

where EchoingPort is the class I would instantiate from.

The api says this about the Exception thrown by newInstance():

InstantiationException - Thrown if this Class represents an abstract class, an interface, an array class, a primitive type, or void; or if the instantiation fails for some other reason .

I printed all the modifiers for the the class, and it is not an interface, not abstract, etc.

The odd thing is, if I run the instantiation code outside orion, EchoingPort instantiates properly.

Questions

--------

Does orion intervene somehow in the instantiation process ?

Does anybody have a clue what I'm doing wrong ?
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