Getting Classloader as null when loading class using Class.forName()

[Abhineet Kapil]

Hi,

I am loading class Test2 from class Test using Class.forName().
But when I try to get the classLoader for class Test2, i get null value.
Both classes are in the same folder.


Class Test2 :

public class Test2 {

	static final String  str = "Test2 class";
		
	static{
		System.out.println("Test2 class loaded ... ");
	}
	
}

Class Test :

public class Test {

	public static void main (String [] args){
			
			Class test2 = null;
			
			try {
				test2 = Class.forName("Test2");
			} catch (ClassNotFoundException e) {
				e.printStackTrace();
			}
			
			System.out.println("Test2  :  "+  test2.getClass().getClassLoader());
			
		}
}

Can anyone please explain why I am getting classloader as null.
Should'nt it return the same classloader as that of class Test.

[Jesper de Jong]

The API documentation of Class.getClassLoader() says:

Returns the class loader for the class. Some implementations may use null to represent the bootstrap class loader. This method will return null in such implementations if this class was loaded by the bootstrap class loader.

Abhineet Kapil wrote:Should'nt it return the same classloader as that of class Test.

Did you try checking what the classloader is that was used to load class Test? Maybe it's also null. Try: Test.class.getClassLoader()

[Abhineet Kapil]

I checked the classloader of Test class. It is not null.

Below is the output :

ClassLoader of Test class : sun.misc.Launcher$AppClassLoader@14fe5c
ClassLoader of Test2 class : null

[Abhineet Kapil]

I have observed different behaviour when I call getClassLoader() through object reference and through Class object.

public class Test {

	public static void main (String [] args){
			
			Class test2 = null;
			Test test = new Test();
			try {
				test2 = Class.forName("Test2");
			} catch (ClassNotFoundException e) {
				e.printStackTrace();
			}
			
			System.out.println("ClassLoader of Test class using classname :  "+  (Test.class.getClass()).getClassLoader());
			System.out.println("ClassLoader of Test class using object reference :  "+  test.getClass().getClassLoader());
			System.out.println("ClassLoader of Test2 class  :  "+  test2.getClass().getClassLoader());
			
		}
}

Output of above code :

ClassLoader of Test class using classname :  null
ClassLoader of Test class using object reference :  sun.misc.Launcher$AppClassLoader@14fe5c
ClassLoader of Test2 class  :  null

So, why is there a difference when getting class loader from a object reference and that from Class name.

[Tony Docherty]

The difference you are seeing is when you are calling getClass().getClassLoader() on a Class object. This is asking for the class loader that loaded the Class object (which is presumably the bootstrap class loader) and not the class loader that loaded the test2 class.
IF you change your code to:

            System.out.println("ClassLoader of Test2 class  :  "+  test2.getClassLoader());  

You will get the answer you expected.

[Abhineet Kapil]

Thanks Tony...

Working perfectly fine now...