Using images

[zjames]

Hi, I am trying to make a Java app which involves displaying images. I use the code

Image = Toolkit.getDefaultToolkit().getImage("img.png");

but it returns an error, "NullPointerException". img.png is in the build folder with all the .class files. Does anyone know why I get this error?

[KevinWorkman]

Is that the actual line you're using? Is that the actual line you get the NPE on? Is Image a variable name? If not, what is the variable name?

[zjames]

yes, that it is the line I get an error and Image is a variable type

[KevinWorkman]

I'm surprised you're getting runtime errors, because that line shouldn't even compile. Compare this:

String = "test"; //won't compile

to this:

String s = "test"; //will compile

Notice the difference?

[zjames]

I type the code wrong my mistake. It was actually

 Image img = Toolkit.getDefaultToolkit().getImage("img.png");

[Fubarable]

The method may not be looking for the file in the build folder but rather in the user directory. To find out where that is, run

System.out.println(System.getProperty("user.dir"));

[zjames]

I have run that command and the output was a file location. I have put the images in there, but still get the same error.

[pbrockway2]

I type the code wrong my mistake. It was actually

 Image img = Toolkit.getDefaultToolkit().getImage("img.png");

I am rather surprised you get a null pointer exception at runtime on this line, whether or not the image exists. For a nonexistent file, running the following:

import java.awt.Image;
import java.awt.Toolkit;

public class Main {
    public static void main(String[] args) {
        Image img = Toolkit.getDefaultToolkit().getImage("abcd.efg");
        System.out.println(img);
    }
}

I get the following output:

sun.awt.image.ToolkitImage@14318bb

Could you verify that the problem is as you described it (even perhaps running the code above)? Or describe what the problem is?

[zjames]

Thanks, I tried running that command and receieved no error.
Don't know what the error was, but I have now renamed the image to abcdef.png and it works fine.