instantiation exception

i dont know how to create an instance of an inner class using classloader? here is my code in java.
plz help. emergency question:-ss

package a;
public class outer{
public outer(){}
public class inner{
public inner(){}
}

}
------------
package test;
public class main{
static void main(){
//how to create an instance of inner class by classLoader.loadclass??
//i have tried but I face instantiation exception
}
}

Can you post more details? What is the name of the classs?
What class and methods are you trying to use to load that class?

Quote:

---

Originally Posted by Norm

Can you post more details? What is the name of the classs?
What class and methods are you trying to use to load that class?

---

tnx for ur reply
i used this code:
public static void main(){
outer o=new outer();
inner i=o.new inner ();
i=(inner)Class.forName("a.outer$inner").newInstanc e();
}

the error was instantiation exception

Can you make a small complete program that compiles, executes and shows the problem?
Be sure to wrap the code in code tags. What you posted won't compile or execute.

<code>
package a;


public class A {

public A(){System.out.println("a constructed");}


public class B{

public B(){System.out.println("b constructed");}

}

}


--------------------------------------------
package helloworld;

import a.A;
import a.A.B;


public class Main {


public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {

A a=new A();
B b=a.new B();
b=(B)Class.forName("a.A$B").newInstance();



}

}
</code>
---------------------------------
output is:

a constructed
b constructed
Exception in thread "main" java.lang.InstantiationException: a.A$B
at java.lang.Class.newInstance0(Class.java:340)
at java.lang.Class.newInstance(Class.java:308)
at helloworld.Main.main(Main.java:25)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

--- Update ---

[CODE]

Quote:

---

package a;


public class A {

public A(){System.out.println("a constructed");}


public class B{

public B(){System.out.println("b constructed");}

}

}




package helloworld;

import a.A;
import a.A.B;


public class Main {


public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {

A a=new A();
B b=a.new B();
b=(B)Class.forName("a.A$B").newInstance();



}

}

---

Please edit your post and wrap your code with
[code=java]
<YOUR CODE HERE>
[/code]
to get highlighting and preserve formatting.

Can you remove the packages. They make the testing too hard to setup.

Quote:

---

Originally Posted by Norm

Please edit your post and wrap your code with
[code=java]
<YOUR CODE HERE>
[/code]
to get highlighting and preserve formatting.

---

ok, really Sorry

Code java:

---

 
package a;
 
 
public class A {
 
    public A(){System.out.println("a constructed");}
 
 
    public class B{
 
        public B(){System.out.println("b constructed");}
 
    }
 
}
 
 
 
package helloworld;
 
import a.A;
import a.A.B;
 
 
public class Main {
 
 
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
 
     A a=new A();
     B b=a.new B();
     b=(B)Class.forName("a.A$B").newInstance();
 
 
 
 
 
    }
 
}

---

output:
a constructed
b constructed
Exception in thread "main" java.lang.InstantiationException: a.A$B
at java.lang.Class.newInstance0(Class.java:340)
at java.lang.Class.newInstance(Class.java:308)
at helloworld.Main.main(Main.java:25)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

Have you researched if this is possible?

Quote:

---

Originally Posted by Norm

Have you researched if this is possible?

---

I have a code that has run before, but now i cant run it. i know there should be a way...

--- Update ---

HooRAY, I found the way

Code java:

---

package helloworld;
 
import a.A;
import a.A.B;
 
/**
 *
 * @author alieh
 */
public class Main {
 
 
 
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
 
 
        Class<B> b=null;
        ClassLoader classLoader = ClassLoader.getSystemClassLoader();
        b = ( Class<B> )Class.forName( "a.A$B",false,classLoader);
 
 
 
 
 
 
 
    }
 
}

---

--- Update ---

Dear Norm,
really tnx for ur attention and reminding me to research;-)

Thanks for sharing the solution.