a question about JDBCCreateBeanClassInstanceCommand

[liu_linux]

Hi, I am reading JBoss 3.2.3 and have a question about the constructor of class JDBCCreateBeanClassInstanceCommand.
There are follow statements in the constructor:
beanClass = theContainer.getBeanClass();
fieldMap = createFieldMap();
selectorMap = createSelectorMap();
// use proxy generator to create one implementation
EntityBridgeInvocationHandler handler = new EntityBridgeInvocationHandler(
theContainer,
fieldMap,
selectorMap,
beanClass);
Class[] classes = new Class[] { beanClass };
ClassLoader classLoader = beanClass.getClassLoader();

Object o = Proxy.newProxyInstance(classLoader, classes, handler);

I don?t understand why Proxy.newProxyInstance() executes successfully. Because the second parameter should be an array only contains Interface type. But in fact, the beanClass is a class type. I have tried a simple example, which is in the same structure with previous statements but encountered exception, here are details:

import java.lang.reflect.*;

interface EntityBean
{
public void fun();
}

abstract class BusinessLogicAbstractClass implements EntityBean
{
public abstract void abstract_fun();
}


class StandardInvocationHandler implements InvocationHandler
{
public Object invoke( Object proxy, Method method, Object[] args)
{
System.out.println( "invoke "+ proxy.getClass());
System.out.println( " Method [" + method.toString()+"]");
return null;
}
}

public class Main
{
public static void main(String[] args)
{
Main obj = new Main();
obj.fun();
}

public void fun()
{

Class beanClass = BusinessLogicAbstractClass.class;

System.out.println(beanClass);

InvocationHandler ih = new StandardInvocationHandler();

Class[] classes = new Class[] { beanClass };
ClassLoader classLoader = beanClass.getClassLoader();

Object o = (BusinessLogicAbstractClass)Proxy.newProxyInstance(classLoader, classes, ih);

try{
Constructor beanProxyConstructor = o.getClass().getConstructor(new Class[]{InvocationHandler.class});

StandardInvocationHandler handler = new StandardInvocationHandler();

BusinessLogicAbstractClass bli =(BusinessLogicAbstractClass) (beanProxyConstructor.newInstance(new Object[]{handler}));

bli.fun();
bli.abstract_fun();
}catch(Exception e){
System.out.println("exception");
}
}
}

I:\java>java Main
class BusinessLogicAbstractClass
Exception in thread "main" java.lang.IllegalArgumentException: BusinessLogicAbstractClass is not an interface
at java.lang.reflect.Proxy.getProxyClass(Proxy.java:340)
at java.lang.reflect.Proxy.newProxyInstance(Proxy.java:552)
at Main.fun(Main.java:44)
at Main.main(Main.java:29)

Could you tell me what?s wrong with the code? I think it is in the same structure with JDBCCreateBeanClassInstanceCommand?s.
Any help is appreciated!

[aloubyansky]

Hi, I am reading JBoss 3.2.3 and have a question about the constructor of class JDBCCreateBeanClassInstanceCommand.
There are follow statements in the constructor:
beanClass = theContainer.getBeanClass();
fieldMap = createFieldMap();
selectorMap = createSelectorMap();
// use proxy generator to create one implementation
EntityBridgeInvocationHandler handler = new EntityBridgeInvocationHandler(
theContainer,
fieldMap,
selectorMap,
beanClass);
Class[] classes = new Class[] { beanClass };
ClassLoader classLoader = beanClass.getClassLoader();

Object o = Proxy.newProxyInstance(classLoader, classes, handler);

I don?t understand why Proxy.newProxyInstance() executes successfully. Because the second parameter should be an array only contains Interface type. But in fact, the beanClass is a class type. I have tried a simple example, which is in the same structure with previous statements but encountered exception, here are details:

import java.lang.reflect.*;

interface EntityBean
{
public void fun();
}

abstract class BusinessLogicAbstractClass implements EntityBean
{
public abstract void abstract_fun();
}


class StandardInvocationHandler implements InvocationHandler
{
public Object invoke( Object proxy, Method method, Object[] args)
{
System.out.println( "invoke "+ proxy.getClass());
System.out.println( " Method [" + method.toString()+"]");
return null;
}
}

public class Main
{
public static void main(String[] args)
{
Main obj = new Main();
obj.fun();
}

public void fun()
{

Class beanClass = BusinessLogicAbstractClass.class;

System.out.println(beanClass);

InvocationHandler ih = new StandardInvocationHandler();

Class[] classes = new Class[] { beanClass };
ClassLoader classLoader = beanClass.getClassLoader();

Object o = (BusinessLogicAbstractClass)Proxy.newProxyInstance(classLoader, classes, ih);

try{
Constructor beanProxyConstructor = o.getClass().getConstructor(new Class[]{InvocationHandler.class});

StandardInvocationHandler handler = new StandardInvocationHandler();

BusinessLogicAbstractClass bli =(BusinessLogicAbstractClass) (beanProxyConstructor.newInstance(new Object[]{handler}));

bli.fun();
bli.abstract_fun();
}catch(Exception e){
System.out.println("exception");
}
}
}

I:\java>java Main
class BusinessLogicAbstractClass
Exception in thread "main" java.lang.IllegalArgumentException: BusinessLogicAbstractClass is not an interface
at java.lang.reflect.Proxy.getProxyClass(Proxy.java:340)
at java.lang.reflect.Proxy.newProxyInstance(Proxy.java:552)
at Main.fun(Main.java:44)
at Main.main(Main.java:29)

Could you tell me what?s wrong with the code? I think it is in the same structure with JDBCCreateBeanClassInstanceCommand?s.
Any help is appreciated!