I can't load a file with getResource

[Nick Petas]

I have this line in my code but it returns null although the file exists in the same folder as the java class :

  Icon bug = new ImageIcon(getClass().getResource("bug1.png"));  

Any ideas?

[David O'Meara]

getResource has nothing to do with the class location, it is relative to the classpath.
You need to turn your class package into a directory path eg java.lang.String becomes /java/lang/ and then add your file /java/lang/bug1.png

[Nick Petas]

Here is the full code of the class :

   
package myPackage;
//Demonstrating the JLabel class

import java.awt.FlowLayout;	//specifies how components are arranged
import javax.swing.JFrame;	//provides basic window features
import javax.swing.JLabel;	//displays text and images
import javax.swing.SwingConstants;	//common constants used with Swing
import javax.swing.Icon;	//interface used to manipulate images
import javax.swing.ImageIcon;	//loads images


public class LabelFrame extends JFrame {
	
	private JLabel label1;	//JLabel with just text
	private JLabel label2;	//JLabel constructed with text and icon
	private JLabel label3;	//JLabel with added text and icon
	
	//LabelFrame constructor adds JLabels to JFrame
	public LabelFrame() {
		super("Testing JLabel");
		setLayout(new FlowLayout());	//set frame layout
		
		//JLabel constructor with a string argument
		label1 = new JLabel("Label with text");
		label1.setToolTipText("This is label1");
		add(label1);	//add label1 to JFrame
		
		//JLabel constructor with string, Icon and alignment arguments
		Icon bug = new ImageIcon(getClass().getResource("bug1.png"));
		label2 = new JLabel("Label with text and icon", bug, SwingConstants.LEFT);
		label2.setToolTipText("This is label2");
		add(label2);	//add label2 to JFRame
		
		label3 = new JLabel();	//JLabel constructor no arguments
		label3.setText("Label with icon and text at bottom");
		label3.setIcon(bug);	//add icon to JLabel
		label3.setHorizontalTextPosition(SwingConstants.CENTER);
		label3.setVerticalTextPosition(SwingConstants.BOTTOM);
		label3.setToolTipText("This is label3");
		add(label3);	//add label3 to JFrame
	}

}

 

[Rob Spoor]

Nick Petas wrote:I have this line in my code but it returns null although the file exists in the same folder as the java class :

  Icon bug = new ImageIcon(getClass().getResource("bug1.png"));  

Any ideas?

David is partly wrong. If the file is in the same location as the class file (so LabelFrame.class, not LabelFrame.java) then it is on the class path and it should be loaded properly. I think in your case you've put the image in the same folder with the source file, not the class file.

[Nick Petas]

Thank you guys for your help.I used System.getProperty("java.class.path") temprorary to see what is the classpath and then I moved the png file from the src directory to the bin directory that I've go from the getProperty command.
Thank you for your help.

(Here is a nice link about classpath : http://en.wikipedia.org/wiki/Classpath_(Java) )

[Nick Petas]

The only remaining warning from eclipse is that :


Description Resource Path Location Type
The serializable class LabelFrame does not declare a static final serialVersionUID field of type long LabelFrame.java /SimpleGui2/src/myPackage line 12 Java Problem


Any ideas guys of what it is?

[David O'Meara]

Rob Prime wrote:David is partly wrong. If the file is in the same location as the class file (so LabelFrame.class, not LabelFrame.java) then it is on the class path and it should be loaded properly. I think in your case you've put the image in the same folder with the source file, not the class file.

True, I discovered this in the API too

[David Newton]

Nick Petas wrote:The only remaining warning from eclipse is that :

Description Resource Path Location Type
The serializable class LabelFrame does not declare a static final serialVersionUID field of type long LabelFrame.java /SimpleGui2/src/myPackage line 12 Java Problem

Any ideas guys of what it is?

Yes, it's a warning that your serializable class isn't declaring a serialVersionUID field.

http://java.sun.com/developer/technicalArticles/Programming/serialization/

You may or may not actually care; you can either suppress the warning, or give it a serialVersionUID.

[Rob Spoor]

Nick Petas wrote:then I moved the png file from the src directory to the bin directory that I've go from the getProperty command.

I just love being right

[Nick Petas]

I have again the same problem, this time before the constructor.
Check this code :

//JComboBox that displays a list of image names

package myPackage;

//imports
import java.awt.FlowLayout;

import java.awt.event.ItemListener;
import java.awt.event.ItemEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JComboBox;
import javax.swing.Icon;
import javax.swing.ImageIcon;

public class ComboBoxFrame extends JFrame{
	
	private JComboBox imagesJComboBox;	//combobox to hold names of icons
	private JLabel label;	//label to display selected icon
	
	private static final String[] names = {"big1.gif", "bug2.gif", "travelbug.gif", "buganim.gif"};
	private Icon[] icons = {
			new ImageIcon(getClass().getResource(names[0]) ),//<------------------------------------------------------------------------null error here (names[0] is "big1.gif" before this line tries to execute
			new ImageIcon(getClass().getResource(names[1]) ),
			new ImageIcon(getClass().getResource(names[2]) ),
			new ImageIcon(getClass().getResource(names[3]) ) };
	
	//ComboBoxFrame constructor adds JComboBox to JFrame
	public ComboBoxFrame()
	{
		super("Testing JComboBox");
		setLayout(new FlowLayout());	//set frame layout
		
		imagesJComboBox = new JComboBox(names);	//set up JComboBox
		imagesJComboBox.setMaximumRowCount(3);	//display three rows
		
		imagesJComboBox.addItemListener(
				new ItemListener()	//anonymous inner class
				{
					//handle JComboBox event
					public void itemStateChanged(ItemEvent event)
					{
						//determine whether item selected
						if (event.getStateChange() == ItemEvent.SELECTED)
							label.setIcon( icons[imagesJComboBox.getSelectedIndex()] );
					}//end method itemStateChanged
				}//end anonymous inner class
		);//end call to addItemListener
		
		add(imagesJComboBox);	//add combobox to JFrame
		label = new JLabel(icons[0]);	//display first icon
		add(label);
	}//end ComboBoxFrame constructor

}//end class ComboBoxFrame

Any ideas guys on this one?(the images are properly placed in the bin directory of the project along with the classes.

[Nick Petas]

That was easy.I typed big1.gif instead of bug1.gif !