question on dynamic class loading

[zhanghong920]

Hi all,

I'm trying to read the class name from a configure file, and then create an instant of it. The related classes are:

//G:
public interface G{
public void setProperties(Properties p);
public void setDBConnect();
}

//F:
public class F extends SF implements G{
//implement setProperties(), setDBConnect(), and other overriding methods defined in the superclass SF.
}

//A:
public class A{
public static void main(..){
String className = ... //it's: abb.dlt.oai.client.F
Properties p = ... //build according to the configuring

Object obj = Class.forName(className).newInstance();
G obj = (G) obj;
obj.setProperties(p);
}
}

Some other unrelated lines are omitted here. The problem is: it's fine in compiling. But when I run: "java A",there's an error message as below:

Exception in thread "main" java.lang.IncompatibleClassChangeError: class abb.dlt.oai.client.F has interface abb.dlt.oai.client.G as super class
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:130)
at abb.dlt.oai.client.A.main(A.java:63)

Anything I missed? Thanks a lot,

zhanghong920

 

[larsjaco]

The exception says that F has the interface G as super class. This is clearly not the case now, but maybe it was before?

The Javadoc on java.lang.IncompatibleClassChangeError suggests, that you might need to recompile some of the classes.


Lars

 

[zhanghong920]

You're right! nothing wrong after I recompile them. Thanks a lot.

zhanghong920

 

[libaax]

>> Object obj = Class.forName(className).newInstance();
G obj = (G) obj;

is't My eyes, or "obj" is declared twice above? That could be ur problemo.