IllegalAccessException on using newInstance()

the Constructor isn't accessible, probably for some obscure security reason. there's a workaround:

package my.pkg;

import java.io.*;

import java.lang.reflect.*;

public class MainLoader extends ClassLoader{

public Class loadClass(String name) throws ClassNotFoundException {

if (name.startsWith("Loaded")) {

return findClass(name);

} else {

return super.loadClass(name);

}

}

public Class findClass(String name) throws ClassNotFoundException {

try {

// we load the class from current directory

File f = new File(name.replace(".", "/") + ".class");

int len = (int) f.length();

byte[] buf = new byte[len];

FileInputStream fis = new FileInputStream(f);

fis.read(buf);

System.out.println("Loading..." + name);

return defineClass(name, buf, 0, buf.length);

} catch (Exception exp) {

throw new ClassNotFoundException(exp.getMessage());

}

}

public static void main(String[] args) throws Exception {

MainLoader loader = new MainLoader();

Class myLoad = loader.loadClass("LoadedClass");

Class appLoad = Class.forName("LoadedClass");

if(myLoad == appLoad)

System.out.println("They are equal");

else

System.out.println("They are not equal");

// here I'm using the Constructor instead of the class

// and making it accessible, since that's the problem

Constructor con = myLoad.getConstructor(new Class[0]);

con.setAccessible(true);

con.newInstance();

// myLoad.newInstance();

System.out.println(myLoad.getClassLoader());

System.out.println(LoadedClass.class.getClassLoader());

System.out.println(appLoad.getClassLoader());

}

}

class LoadedClass{

String name;

int age;

LoadedChild lc;

public LoadedClass(){

System.out.println("Empty ctor");

}

void setName(String s){

name = s;

}

String getName(){

return name;

}

void setAge(int age){

this.age = age;

}

int getAge(){

return this.age;

}

}

class LoadedChild{

String address;

void setAddress(String s){

address = s;

}

String getAddress(){

return address;

}

}

notice I've instantiated using a Constructor, rather than the class object, and set it to be accessible, first

georgemca at 2007-7-8 23:58:14 >

> notice I've instantiated using a Constructor, rather

> than the class object, and set it to be accessible,

> first

For some reason I cannot understand this is what happens when I try

using the ctor approach:

C:\Java>java MainLoader

Loading...LoadedClass

They are not equal

Exception in thread "main" java.lang.NoSuchMethodException: LoadedClass.<init>()

at java.lang.Class.getConstructor0(Unknown Source)

at java.lang.Class.getConstructor(Unknown Source)

at MainLoader.main(MainLoader.java:39)

krishy5a at 2007-7-8 23:58:14 >

> Hmm, newInstance() seems to require the constructor

> to be public.

Not really. Having the ctor public seems to have no effect. If the it is

public this is the error I get:

Exception in thread "main" java.lang.IllegalAccessException: Class MainLoader can not access a member of class LoadedClass with modifiers "public"

at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:65)

at java.lang.Class.newInstance0(Class.java:344)

at java.lang.Class.newInstance(Class.java:303)

at MainLoader.main(MainLoader.java:38)

krishy5a at 2007-7-8 23:58:14 >