Sample program for Log4J and Class Loader

public class MyClassLoader {

public static Method findMethod(String name,Method methods[])

{

Method method = null;

for (int i=0; i < methods.length; i++)

if (methods[i].getName().equals(name))

{

method=methods[i];

i = methods.length;

}

return method;

}

public static void main (String args[])

{

Logger log = Logger.getLogger(MyClassLoader.class);

String cls = “com.test.loader.TestClass”;

String mtd = “sayHaiTo”;

Object objClass = null;

try

{

log.debug(cls +” class goint to be loaded”);

Class clazz = Class.forName(cls);

objClass = clazz.newInstance();

log.debug(“Loading class success : ” + cls );

Method methods[] = clazz.getMethods();

log.debug(methods.length + ” Methods found for ” + cls );

for (int i=0; i < methods.length; i++)

log.debug( i+1 + “) ” + methods[i].getName());

log.debug(“Finding Method ‘” + mtd + “‘ in class ‘”+cls+”‘”);

Method method = findMethod(mtd,methods);

if (method == null)

log.warn(“Method ‘” + mtd + “‘ not found in class ‘” + cls + “‘”);

else

log.info(“Method ‘” + mtd + “‘ found in class ‘” + cls + “‘”);

log.debug(“invoking Method ‘” + mtd + “‘ in class ‘” + cls + “‘”);

method.invoke(objClass,new String[]{“Ram”});

log.debug(“initializing method sayMyAge”);

Method method1 = findMethod(“sayMyAge”,methods);

log.debug(“calling method sayMyAge”);
method1.invoke(objClass,new Object[]{new Integer(25)});

}

catch(ClassNotFoundException e)

{

log.error(“Loader class ‘” + cls + “‘ Not Found.”);

}

catch(IllegalAccessException e)

{

log.error(“Illegal Access of class ‘” + cls + “‘ .”);

}

catch(Exception e)

{

log.error(“Exception in class ‘” + cls + “‘ Invocation. Thrown : ” + e.getMessage());

}
}
}