Remote Class Loading

The URLClassLoader class was created specifically to facilitate the downloading of classes over a network. Three constructors are provided, the first of which simply takes a URL[] as an argument using the default ClassLoader.

Code:

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URLClassLoader(URL[] urls)
URLClassLoader(URL[] urls, ClassLoader parent)
URLClassLoader(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory)

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If the URL or URL's stored within the URL[] end with '/' then a directory is assumed or a .jar file can be specified.

Code:

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import java.net.URL;
import java.net.URLClassLoader;
import java.net.MalformedURLException;

public class NetworkClassLoader{ 
 public static void main(String[] args){
  URLClassLoader urlcl = null;
  Class c = null;
 try{
  urlcl = new URLClassLoader(new URL[]{new URL("http://www.javacourses.com/classes/test.jar")});
 }catch(MalformedURLException me){
  System.out.println(me + " is not a valid URL");
 }
  try{
  c = urlcl.loadClass("Tester");
  }catch(ClassNotFoundException cnf){
    System.out.println("Class could not be found");
  }
  try{
    Object o = c.newInstance();
  }catch(InstantiationException ie){
    System.out.println("Could not create an instance of the class");
  }catch(IllegalAccessException iae){
  }
 }
}

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