Develop Reference

JAVA getResourceAsStream() real path string interpretation of a file

I am using NetBeans 8.0.2 (I know there already is v8.2 but it has a lot of bugs for me so I got back to v8.0.2) and I need a string path to my .obj file for a parameter attribute like this:
api.parameter("filename", "obj/someFile.obj");
Above example worked in a previous version of my app where I had that .obj file placed in a folder called "obj" in the same directory as my .jar file, but now as I am trying to rather include it in the JAR itself with code:
api.parameter("filename", MyClass.class.getResourceAsStream("/someFile.obj").toString());
...it is not working anymore as the path string interpretation is not a path to a file, it looks more like this:
java.io.BufferedInputStream#215d7ea7
...where, of course, my code is expecting something like normal path string, I would said something in this pseudo-code manner:
api.parameter("filename", "<this.jar>/someFile.obj");
So after a fiddling a bit around StackOverflow I've found pieces of code that I thought could actually enable me to directly place that path as a string:
URL jar = MyClass.class.getProtectionDomain().getCodeSource().getLocation();
api.parameter("filename", jar + "/someFile.obj");
But surprisingly although I checked several times if the file actually really exist in my built jar file (and yes, it is there in the root) it still gives me this error:
java.io.FileNotFoundException: file:\Z:\_JAVA_\MyProject_0_018\dist\bin\myjar.jar\someFile.obj <The filename, directory name, or volume label syntax is incorrect>
And I am 100% sure the name of the file is correct, also its placement in the root of my jar file.
Or does it actually thinks that myjar.jar is a directory?
I am desperately trying to find a solution to this "path string" mess.

Your protection domain's code source location likely returns not what you'd expect it to.
You should use getResource(name) directly, like this:
URL locator = MyClass.class.getResource("someFile.obj");
api.parameter("filename", locator.toString());

Java throwing NullPointerException when loading Images using getClass().getResource()

I have an Applet I'm trying to embed into a html file after packaging into a jar file.
Images are loaded in the main Applet Class with the following line
return getImage(getClass().getResource("/../content/"+path));
This works when running through eclipse but when I export it to a jar file I get a Null Pointer Exception. I've done some googling and I've tried to use getResourceAsStream with the following code
InputStream is = new BufferedInputStream(
getClass().getResourceAsStream("/../content/"+path));
return ImageIO.read(is);
but this doesn't work through eclipse.
Content is the top level directory of the images and path is the specified path to the required image. The applet is in a folder called game, which is at the same level as content

It was a comment now i answered it here (as OP said it did help): try putting the content into the same package as the class thats accessing the content and change the paths accordingly and see if that helps. If it does, its a problem with your paths.

I had the same issue. But solved it using :-
<ClassName>.class.getClass().getResource(urlString);
Hope this helps...

You could try this instead.
getClass().getClassLoader().getResourceAsStream(name)
Also, your path looks a bit weird. /.. basically means the parent directory of the root, which cannot possibly work.

ClassLoader loading the wrong instance of a file

So I see there has already been a post very similar to this issue, however I am in a situation where I have no power to specify the location of this file within my jar and so am hoping someone is aware of a solution to get around this.
So I currently use the following snippet to obtain a file as an input stream, the file 'plugin.xml' is located at the root of the jar and I cannot change this location as another piece of software (dynatrace) creates this file and determines its location.
the standard snippet:
InputStream is = JmxPlugin.class.getResourceAsStream("/plugin.xml");
Now I am aware that the issue is that the ClassLoader is picking up the first file which matches the name 'Plugin.xml' along the classpath (one which isn't in my jar, yay).
Can anyone think of a way to ensure I pick up the correct file without having to move it? The relative path of my class in the jar is com/something/jmx/JmxPlugin.class.
(Id rather not have to unpack the jar in memory).
Many thanks for any contributions,

I'm not absolutely sure, but seems like Thread.currentThread().getContextClassLoader().getResourceAsStream("/plugin.xml") may solve your issue. If not, you'll have to create your own ClassLoader and resolve the issue there.

The simplies way is to move your jar in classpath to be the first containing Plugin.xml,
Another approach is to use getResource() to locate your jar file:
URL myJar=JmxPlugin.class.getResource("/"+JmxPlugin.class.getName().replace(".","/")+".class");
then use this URL to open jar file and extract Plugin.xml.

Add images to jar

I want to set icon to my JFrame. I do the following:
Image icon = Toolkit.getDefaultToolkit().getImage("src/images/icon.jpg");
this.setIconImage(icon);
It works fine when I run this code from netbeans, but when I try to run this code from jar file, images are not shown in my JFrame. I have tried to load images as resources:
this.setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("/src/images/icon.jpg")));
but when I run this code it fails with NullPointerException
Uncaught error fetching image:
java.lang.NullPointerException
at sun.awt.image.URLImageSource.getConnection(URLImageSource.java:99)
at sun.awt.image.URLImageSource.getDecoder(URLImageSource.java:113)
at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.java:240)
at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:172)
at sun.awt.image.ImageFetcher.run(ImageFetcher.java:136)
How can I do this work?
edit:
Thanks to all,
the problem was solved by specifying image as
Toolkit.getDefaultToolkit().getImage(getClass().getClassLoader().getResource("images/icon.JPG"))
As for it seems rather weird, and would be better if it was like
this.setIconImage(new ImageIcon(pathToIcon).getImage());

Assuming your JAR file has a top level directory called images, you can use either:
getClass().getResource("/images/icon.jpg") or
getClass().getClassLoader().getResource("images/icon.jpg")

Looking at the source code of URLImageSource, it appears that the reason that getConnection throws an NPE is that it has a null for the url. And that leads me to suspect that
getClass().getResource("/src/images/icon.jpg")
is returning null. It would do that if it could not locate a resource with that pathname.
I bet that the problem is that you've got the path wrong.
To prove / disprove this, you should run jar tvf on the JAR file, and look for the line that matches "icon.jpg". Is the corresponding pathname the same as what you are using? If not, use the pathname from the matching line in the getResource call and it should work. Alternatively, if the file doesn't show up at all, look at the NetBeans build configs that tell it what to put in the JAR file. (I'm not a NetBeans user, so I can't say where you would need to look ...)
If that leads you absolutely nowhere, another possibility is that getClass().getResource(...) is using a classloader that doesn't know about the JAR file containing the image. (This seems pretty improbable to me ...)

getResource() loads a resource from classpath, not an OS path, and the after compilation your classpath will not include the /src folder, but rather just its contents. So you'd better try /images/icon.jpg.
Also you may find this discussion somewhat useful.

This should do it assuming you can import javax.imageio.ImageIO:
Image icon = ImageIO.read(this.getClass().getResource("/src/images/icon.jpg"));
this.setIconImage(icon);

.."/src/images/icon.jpg"..
The '/src' prefix of the address seems suspicious. Many apps. will provide separate 'src' and 'build' directories, but it normally ends up that the 'src' prefix is not used in the resulting Jar. I recommend trying..
.."/images/icon.jpg"..
& also triple checking that the image is in the location of the Jar that the code is expecting to find it.

For this to work, you should access the images from a directory relative to some fixed class.
For example, if the image files are saved in a directory "images" on the same level as the Toolkit.class, then
this.setIconImage(Toolkit.getDefaultToolkit().getImage(Toolkit.class.getResource("images/icon.jpg")));
should work.

You can simply create a package inside the main source, and incluse your images in this package. Then, just call the images in your main class like:
ImageIcon a = new ImageIcon(MainClass.class.getResource("/Package/Image.jpg"));

JFrame f = new JFrame("Edit Configure File");
//Image image = ImageIO.read(getClass().getResource("images/ctx.Icon"));
f.setIconImage(new ImageIcon("images/ctx.PNG").getImage());//this works for me finally
//f.setIconImage(image);
//f.setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("images/ctx.PNG")));

Regarding Help File in JAVA

I'm new to help file creation in java. I have created a help file "sample.chm" with a 3rd party tool, added it to a java program with package name as "help" calling with runtime class and build the jar. When I run the jar file it is giving me an error that the "file cannot be found, null pointer Exception". I have given a relative path to identify the file like "../help/sample.chm" still it is not working and I tried with various classes to ientify the path. But still the same error.
Request you to please help me in fixing it.
The jar can be placed in different systems and should open this help file with out any issues.
I hope my explanation is sufficient you to identify the problem.
Regards,
Chandu

If you have a file inside a jar, you can't access it as you normally would. You can access it like this:
URL helpFile=Thread.currentThread().getContextClassLoader().getResource("help/sample.chm");
The method used above (getResource) will return a URL; if you want, you can get it as an InputStream as well by using getResourceAsStream instead.

At least a workaround unless a better solution pops up. Use the this.getClass().getClassLoader().getResource way to get an inputstream to the help file inside the jar.
Copy the bytes to a new help file in the target systems temp folder and use this extracted file with the external help file viewer.