In certain scenario, you may need to load some classes which are not in your classpath.
Java Example
Assume folder “c:\\other_classes\\” is not in your project classpath, here’s an example to show how to load a Java class from this folder. The code and comments are self-explanatory.
import java.io.File;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.CodeSource;
import java.security.ProtectionDomain;
public class App{
public static void main(String[] args) {
try{
File file = new File("c:\\other_classes\\");
//convert the file to URL format
URL url = file.toURI().toURL();
URL[] urls = new URL[]{url};
//load this folder into Class loader
ClassLoader cl = new URLClassLoader(urls);
//load the Address class in 'c:\\other_classes\\'
Class cls = cl.loadClass("com.mkyong.io.Address");
//print the location from where this class was loaded
ProtectionDomain pDomain = cls.getProtectionDomain();
CodeSource cSource = pDomain.getCodeSource();
URL urlfrom = cSource.getLocation();
System.out.println(urlfrom.getFile());
}catch(Exception ex){
ex.printStackTrace();
}
}
}
Output
/c:/other_classes/
You will notice this class is loaded from “/c:/other_classes/“, which is not in your project classpath.
Hi, can I specify JARs in the path? let say multiple jars dependents on one another? Thanks.
The class file should be present as c:\other_classes\Address.class or c:\other_classes\com\mkyong\io\Address
How to use the methods of this class? Would it be possible without using reflection ?