How to load class from jar file dynamically?

After I run my Java applicatoin, I need configuring
the classpath of jvm to load some classess inside a
jar file into the same jvm.How can I achive that?
I mean, when I run my Java application, I don't know
where the jar file is, what the jar file name is. All
depends on the user to tell the jvm the details
through some UI. I've tried to write:
System.setProperty("java.class.path",
"c:\myClass.jar");Class.forName("MyClass"); but
failed.That won't work. By the time it gets to your code it already has a copy of the original. You can't change it (short of modifying the JVM.)
Can you tell my why and how?The usual way is to use a custom classloader.
You can start by looking at java.net.URLClassLoader.

Similar Messages

Unable to load classes from jar files inside APP-INF/lib in EAR.

Weblogic version: 10.3.3
Platform: Linux x86-64 bit
We deployed an ear packaged with all the common library jars inside APP-INF/lib. Deployment was successful.
for some reason, it is always giving ClassNotFoundException for the classes inside the jars. This does not happen
in 10.3.2 version of weblogic.
We tried to add them to domain/lib directory (instead of APP-INF/lib) but still it is not able to resolve the classes.
Any pointers would be appreciated.

try using prefer-web-inf-classes in the weblogic.xml file in your WAR file
or using prefer-application-packages in the weblogic-application.xml file in your EAR.

Loading library from jar file

Hi all,
My question is can we load library from jar file using System.load() method.
ex:
myJar.jar
|
|----com.test.common.Util
which conatins a method to load library from jar file itself, before that i used to load from File
|---libraries/MozillaParser/......
Iam able load from Local system,
File parserLibraryFile = new File("libraries/MozillaParser" + EnviromentController.getSharedLibraryExtension());
File mozillaDistBinDirectory = new File("libraries/mozilla.dist.bin."+EnviromentController.getOperatingSystemName());
MozillaParser.init(parserLibraryFile.getAbsolutePath() , mozillaDistBinDirectory.getAbsolutePath());
but i am unable to load from jar file
URL url = ClassLoader.getSystemClassLoader().getResource("libraries/MozillaParser" + EnviromentController.getSharedLibraryExtension());
URL url1 = ClassLoader.getSystemClassLoader().getResource("libraries/mozilla.dist.bin."+EnviromentController.getOperatingSystemName());
MozillaParser.init(url.toString(), url1.toString());
Thanks in advance.

That's a really confusing post.
The easiest way to make sure you can use the classes in a jar file is to copy the jar file to the "/jre/lib/ext" subfolder of your JDK. These classes will be visible to all applications.

Problem loading image from jar file referenced by jar file

First, I searched this one and no, I didn't find an answer. Loading images from jar files has been pretty much done to death but my problem is different. Please read on.
I have my application, a straight up executable running from Eclipse. It uses a jar file, call it JarA. JarA launches a GUI that is located in another jar file. Call it JarB. To recap:
My application calls JarA -> JarA loads classes from JarB -> JarB looks for images to place in a GUI it wants to show on the screen
When JarB goes to load an image the following happens:
java.lang.NullPointerException
     at sun.misc.URLClassPath$3.run(URLClassPath.java:316)
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.misc.URLClassPath.getLoader(URLClassPath.java:313)
     at sun.misc.URLClassPath.getLoader(URLClassPath.java:290)
     at sun.misc.URLClassPath.findResource(URLClassPath.java:141)
     at java.net.URLClassLoader$2.run(URLClassLoader.java:362)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findResource(URLClassLoader.java:359)
     at java.lang.ClassLoader.getResource(ClassLoader.java:977)
     at org.cubrc.gmshell.gui.MainWin.preInit(MainWin.java:152)
     at org.cubrc.gmshell.gui.MainWin.<init>(MainWin.java:135)
The code from JarB that loads the image looks like this:
          URL[] oSearch = {Main.class.getResource("images/")};
          URLClassLoader oLoader = new URLClassLoader(oSearch);
          imgIcon = new ImageIcon(oLoader.getResource("icon.gif"));
          imgMatchRunning = new ImageIcon(oLoader.getResource("gears.gif"));
          imgMatchStill = new ImageIcon(oLoader.getResource("gears-still.gif"));
          imgMagnify = new ImageIcon(oLoader.getResource("magnify.gif"));This looks right to me and JarB certainly has an images directory with those files. But I'm in hell right now because I don't know where to place the images to make this work or if you can even attempt to load images with a dependency chain like this.
Any help very appreciated!

Have you tried to move your image-files out of the jar file and place them in the sam folder as the jar-file? I think that would help.
When you try to load the image-file you get the NullPointerException because the program tries to read a file it can't find. Remember that a jar file IS a file and not a directory.
If you want to read somthing inside the jar-file you need to encode it first.
Have you tried to read the jar-file with winRar. It makes it easy to add and remove files in your jar-file.

Please help: Example how to peploy application from jar file step by step

Please help: Example how to peploy application from jar file step by step.
All help appreciated
Mike

Thanks I will try these links
Mike
"Slava Imeshev" <[email protected]> wrote:
Hi Mike,
These links could be useful:
http://e-docs.bea.com/wls/docs61////adminguide/appman.html
http://e-docs.bea.com/wls/docs61////quickstart/quick_start.html
http://e-docs.bea.com/wls/docs61//////ConsoleHelp/application.html
http://e-docs.bea.com/wls/docs61///programming/environment.html
Regards,
Slava Imeshev
"Mike" <[email protected]> wrote in message
news:3ca0e94c$[email protected]..
Please help: Example how to peploy application from jar file step bystep.
All help appreciated
Mike

How to load images from css file in JavaFX 8

I have this css file which loads images in JavaFX 8 application:
#pill-left {
    -fx-padding: 5;
     -fx-border-image-source: url("/com/dx57dc/images/left-btn.png");
    -fx-border-image-slice: 4 4 4 4 fill;
    -fx-border-image-width: 4 4 4 4;
    -fx-border-image-insets: 0;
    -fx-border-image-repeat: stretch;
     -fx-background-color: null !important;
#pill-left:selected { -fx-border-image-source: url("/com/dx57dc/images/left-btn-selected.png"); }
#pill-left .label {
    -fx-text-fill: #d3d3d3;
    -fx-effect: dropshadow( one-pass-box , rgba(0,0,0,0.75) , 0, 0.0 , 0 , -1 );
#pill-left:selected .label {
    /* -fx-text-fill: black; */
    -fx-text-fill: white;
    -fx-effect: dropshadow( one-pass-box , white , 0, 0.0 , 0 , 1 );
#pill-center {
    -fx-padding: 5;
     -fx-border-image-source: url("/com/dx57dc/images/center-btn.png");
    -fx-border-image-slice: 4 4 4 4 fill;
    -fx-border-image-width: 4 4 4 4;
    -fx-border-image-insets: 0;
    -fx-border-image-repeat: stretch;
     -fx-background-color: null !important;
#pill-center:selected { -fx-border-image-source: url("/com/dx57dc/images/center-btn-selected.png"); }
#pill-center .label {
    -fx-text-fill: #d3d3d3;
     -fx-effect: dropshadow( one-pass-box , rgba(0,0,0,0.75) , 0, 0.0 , 0 , -1 );
#pill-center:selected .label {
    -fx-text-fill: black;
    -fx-effect: dropshadow( one-pass-box , white , 0, 0.0 , 0 , 1 );
#pill-right {
    -fx-padding: 5;
    -fx-border-image-source: url("/com/dx57dc/images/right-btn.png");
    -fx-border-image-slice: 4 4 4 4 fill;
    -fx-border-image-width: 4 4 4 4;
    -fx-border-image-insets: 0;
     -fx-border-image-repeat: stretch;
    -fx-background-color: null !important;
#pill-right:selected { -fx-border-image-source: url("/com/dx57dc/images/right-btn-selected.png"); }
#pill-right .label {
     -fx-text-fill: #d3d3d3;
    -fx-effect: dropshadow( one-pass-box , rgba(0,0,0,0.75) , 0, 0.0 , 0 , -1 );
#pill-right:selected .label {
    -fx-text-fill: black;
    -fx-effect: dropshadow( one-pass-box , white , 0, 0.0 , 0 , 1 );
The images are located at the Java package com.dx57dc.images
In Java 7_25 this code works as expected but in JavaFX 8 b99 I get this error:
ava.lang.NullPointerException
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1129)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:1598)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1520)
at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:233)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:199)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1249)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:1598)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1520)
at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:233)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:199)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1249)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:1598)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1520)
at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:99)
at com.sun.javafx.tk.quantum.AbstractPainter.paintImpl(AbstractPainter.java:210)
at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:95)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)
at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:129)
at java.lang.Thread.run(Thread.java:724)
D3D Vram Pool: 13,331,480 used (5.0%), 13,331,480 managed (5.0%), 268,435,456 total
20 total resources being managed
4 permanent resources (20.0%)
1 resources locked (5.0%)
7 resources contain interesting data (35.0%)
0 resources disappeared (0.0%)
D3D Vram Pool: 13,331,480 used (5.0%), 13,331,480 managed (5.0%), 268,435,456 total
20 total resources being managed
4 permanent resources (20.0%)
1 resources locked (5.0%)
7 resources contain interesting data (35.0%)
0 resources disappeared (0.0%)
D3D Vram Pool: 13,331,480 used (5.0%), 13,331,480 managed (5.0%), 268,435,456 total
20 total resources being managed
4 permanent resources (20.0%)
1 resources locked (5.0%)
7 resources contain interesting data (35.0%)
0 resources disappeared (0.0%)
What is the proper way to load images from css in Java 8?
Ref
How to load images from css file in JavaFX 8 - Stack Overflow

There is nothing special to do - you execute the statement from your program just like any other SQL statement. The only thing to be aware of are the privilege/permission issues:
When loading from a file on a client computer:
READ CLIENT FILE privilege is also required for the database user.
Read privileges are required on the directory being read from.
The allow_read_client_file database option must be enabled.
The read_client_file secure feature must be enabled.
Revoking these privileges is also the only way you can prevent a user from executing the statement.

How to load an applet jar file?

Hello everyone,
I have an applet that uses my own jar file and approximately 6 third party jar files. I set up jar indexing (jar -i) which will download the jar files when they are needed. All seems to work well, but now I want to manually load the jar files which I cannot get working.
When the applet starts, about 1/2 of the jar files are downloaded (because they are needed at startup). I then want to load the additional jar files in the background, after the gui is initialized. I have tried this using the below thread which is executed from within the applet's start method:
// Try to load additional jar files in background by loading a class from each jar file.
Thread loadClass = new Thread() {
public void run() {
    System.out.println("Loading classes...");
    try {
      // Tried loading classes this way, doesn't work.
      getClass().getClassLoader().loadClass("pkg1.Class1");
      getClass().getClassLoader().loadClass("pkg2.Class2");
      getClass().getClassLoader().loadClass("pkg3.Class4");
      getClass().getClassLoader().loadClass("pkg4.Class4");
      /* Loading classes this way doesn't work either.
      Class.forName("pkg1.Class1");
      Class.forName("pkg2.Class2");
      Class.forName("pkg3.Class3");
      Class.forName("pkg4.Class4");
    catch(ClassNotFoundException e) {
      // First attempt to load a class (pkg1.Class1) throws exception.
      System.out.println("Can't find class: " + e.getMessage());
loadClass.start();As you can see from above I am trying to load a class from each of the jar files so that the jar files would load into memory/cache. Unfortunately, it cannot find the classes. These are the errors from the java console:
Loading classes...
Loading: pkg1.Class1
Connecting http://my.server.com/my_dir/pkg1/Class1.class with no proxy
Connecting http://my.server.com/my_dir/pkg1/Class1.class with cookie "JSESSIONID=some_big_long_char_list"
Can't find class: pkg1.Class1
So it appears the jar file is not being downloaded. When I take away the dynamic jar loading (removing the "jar -i" & adding them all to the applet archive list) the thread executes correctly. So I know the class names, etc, are correct. How does one load an applet jar file?
Any help/suggestions are appreciated.

The above error I posted was because I forgot to index the jar files. That is why it couldn't find the jar file. I thought I was getting farther along with my problem, but I apparently just forgot to index the jars. I am now getting the problem that I got yesterday...
The applet freezes/hangs when it hits the thread. The GUI never opens (even though I'm running this thread right after the gui shows). The java console quits responding and the applet just stays the grey screen. I also tried the invoke later that you suggested.
public void start() {
// ...initialize gui...
// Applet freezes and remains grey, also the java console freezes.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
    public void run() {
      System.out.println("Loading classes...");
      try {
        // When I comment out the below forName calls, the thread will still run evidenced through the done print statement.
        Class.forName("pkg1.Class1");
     Class.forName("pkg2.Class2");
     Class.forName("pkg3.Class3");
     Class.forName("pkg4.Class4");
        System.out.println("...Done loading classes");
      catch(Exception e)     {
        System.out.println("Can't find class: " + e.getMessage());
}

Load library from JAR file

Could I ask you guys a stupid question, please?
I have a library as an JAR file. I build my application as another JAR file, which includes that library file.
My manifest file is:
Manifest-Version: 0.1.0
Class-Path: lib/mysql-connector-java-3.0.17-ga-bin.jar
Main-Class: com.myappand the build command:
jar cvfm hello.jar mymanifest -c com -c libThe result hello.jar file built OK. But when I run it, I have to copy library file to the same folder to the app file.
Could you tell me how to load the lib file from hello.jar, instead of the lib file?
Thanks in advance!
Best regards,
Lehoanq

am I right in thinking you've put the mysql jar inside your application jar? jars don't work like that, I'm afraid. it is possible to write a classloader that will load classes from within a jar-inside-a-jar, but it gets rather complicated and messy and isn't worth the hassle to be honest, anyway. we go to some lengths to keep our software modular and separate. imagine, for instance, that a bug is exposed in the mysql driver you're using, and a new release is needed to fix it. the dependency is rooted inside your application, so the whole shebang has to be re-packaged and re-deployed, whereas if your dependencies were inside a lib folder, all that would be needed is to drop the new version of the mysql driver into the lib directory. think "don't put all your eggs in one basket"
what you want to do is possible, and there are tools around to do it for you, too, but IMHO it's not worth the effort

Problem loading Applets from Jar files on 64 bit machine

I am developing an applet (extends Applet but uses swing components) using JDK 1.6 (Though these problems still happen in JDK 1.7) and I am unable to get the applet to load on a 64 bit machine in most cases. The web server(s) are running on localhost and I am connecting on the same machine using a local network ip address (such as 192.168.*.*)
Below are all of my test results. Can someone provide a suggestion for repairing this? The Windows Server machine is a clients computer I access to it via remote desktop but I can't do much with it though I do have administrator rights. The Windows 7 machine is my development platform so I have been able to do extensive testing on it.
This problem is presenting in the following environments when trying to load an applet from JAR files in a HTML document using the Applet or Object tag.
Windows Server 2008 (Intel Chipset)
Tested Browsers:
Internet Explorer 9 (32 bit) - Shows it is blocked by default then simply shows an x when loaded from a web page, same result when loading from local drive.
Windows 7 Home Premium (AMD Chipset)
Tested Browsers:
Firefox 6.0.1 (32 bit) - Java logo shows with spinner, after a few minutes there is finally an error that a class in the jar was not found
Internet Explorer 9 (32 bit) - Java logo shows with spinner, after a few minutes there is finally an error that a class in the jar was not found
Internet Explorer 9 (64 bit) - Java logo shows with spinner and most of the windows desktop manager freezes, keyboard is the only thing that responds so you can alt-tab to another app to regain control of the desktop.
Chrome (32 bit) - Java logo shows with spinner, after a few minutes there is finally an error that a class in the jar was not found
The only way I have been able to get a Java applet to run on a 64 bit machine are the following ways.
Firefox 9 nightly (64 bit) works perfectly! Go Firefox!
Internet Explorer 9 (32 bit) loading directly from drive (c:\...)
Chrome (32 bit) loading directly from drive (c:\...)
Firefox 6.0.1 (32 bit) loading directly from drive (c:\....)
Can someone please help! I've been fighting with this bug for over a week and I can't find anything that will solve it, I have noticed that in some cases if my jar has very little code in it than it will run on the server, but the minute I start adding things to it the jar won't load anymore.

jschell wrote:
rritoch wrote:
I am developing an applet (extends Applet but uses swing components) using JDK 1.6 (Though these problems still happen in JDK 1.7) and I am unable to get the applet to load on a 64 bit machine in most cases.
To clarify...
1. You have tried it on 32 bit machine? Exactly which OS?I tested this on Windows Vista Business which is in 32 bit mode and the applets run without any problems
>
2. Your only 64 bit tests have involved 2008/Win7?
If so then I would suspect something with windows not java. Probably permissions.
The web server(s) are running on localhost and I am connecting on the same machine using a local network ip address (such as 192.168.*.*)
Yes, I haven't tried running the jars on other operating systems.
>
I don't understand that. If you are running on localhost then you should connect to localhost. If running on an IP then you should connect to that. Perhaps you meant that you have tested using both of those?I'm testing using the lan ip address but I'm connecting from the same machine. I've tried localhost and that didn't work so I tried lan ip since that will likely have a different java security context than localhost. At first I was blaming the IIS server but I downloaded the jar directly and using HTTP fox was able to verify that the jar is being sent with the correct mime-type and that the server can upload the jar file without a problem. This leaves me to believe the problem is with Java.

Cannot load component from JAR file.

I got the message : cannot load component ... from JAR file. The class must be compiled and must be on the classpath of the project...
I just add a javabean from a JAR file from Palette manager, then drag and drop it, then got this message.
Can anyone tell me what i was wrong ? Thank you.

Hi,
You should paste your error log here to easy for other to help you.
For your scenario, it is a big chance you didn't include the jar file into your classpath, please check.
Thanks.

How to convert .class into .jar file

Hi,
How to convert .class into .jar file

jsf_VWP5.5.1 wrote:
Hi,
How to convert .class into .jar fileFrom a command prompt, cd to the location of your .class file(s).
If you want to create a simple jar, use: jar -cf Whatever.jar Whatever.class
If you want to compile all .class files in a directory into a jar, use *.class instead.
Now, I'm going to assume you want to create an executable jar... here's how to do that:
1) Create a blank text file; for this example, lets call it main.txt.
2) In the first line of main.txt, type: Main-class: Whatever ('Whatever' should be the name of the class in your program where the main() method is located)
3) Press enter to go to the next line (someone please correct me if I'm wrong, but if you don't insert the line break/CR after the Main-class: statement, this will not work... in my experience, this is true)
4) Make sure you save this file in the same directory as your .class file(s).
5) Type: jar -cmf Whatever.jar main.txt Whatever.class
...and that's about it. For more information on the usage of the jar command and to understand the switches (such as -cmf), try jar --help.
Hope that helps.

How to load data from UTL file to database

Hi All,
I am new in this technologies.
I am facing below problem to load data from utl file to database .
below is the script written by me :
CREATE OR REPLACE PROCEDURE load_data AS
v_line VARCHAR2(2000);
v_file UTL_FILE.FILE_TYPE;
v_dir VARCHAR2(250);
v_filename VARCHAR2(50);
v_1st_Comma NUMBER;
v_2nd_Comma NUMBER;
v_deptno NUMBER;
v_dname VARCHAR2(14);
v_loc VARCHAR2(13);
BEGIN
v_dir := ':f/rashi/dataload';
v_filename := 'fake.txt';
v_file := UTL_FILE.FOPEN(v_dir, v_filename, 'r');
LOOP
BEGIN
UTL_FILE.GET_LINE(v_file, v_line);
EXCEPTION
WHEN no_data_found THEN
exit;
END;
v_1st_Comma := INSTR(v_line, ',' ,1 , 1);
v_2nd_Comma := INSTR(v_line, ',' ,1 , 2);
v_deptno := SUBSTR(v_line, 1, v_1st_Comma-1);
v_dname := SUBSTR(v_line, v_1st_Comma+1, v_2nd_Comma-v_1st_Comma-1);
v_loc := SUBSTR(v_line, v_2nd_Comma+1);
DBMS_OUTPUT.PUT_LINE(v_deptno || ' - ' || v_dname || ' - ' || v_loc);
INSERT INTO don
VALUES (v_deptno, UPPER(v_dname), UPPER(v_loc));
END LOOP;
UTL_FILE.FCLOSE(v_file);
COMMIT;
END;
show error
I am getting the below errors:
LINE/COL ERROR
3/8 PL/SQL: Item ignored
3/8 PLS-00201: identifier 'UTL_FILE' must be declared
15/1 PL/SQL: Statement ignored
15/1 PLS-00320: the declaration of the type of this expression is
incomplete or malformed
20/1 PL/SQL: Statement ignored
20/19 PLS-00320: the declaration of the type of this expression is
incomplete or malformed
36/1 PL/SQL: Statement ignored
LINE/COL ERROR
36/17 PLS-00320: the declaration of the type of this expression is
incomplete or malformed
could anyone please advice me on above error.
thanx.

First of all, is file located on (or is accessible from) database server? If not - you can't load it neither with UTL_FILE nor with external table. You need to use client side tool like SQL*Loader or write your own client side load. If file is accessible from database server, then, as sb92075 noted, external table (assuming you are not on some ancient Oracle version) is the way to go.
SY.

Instantiate class from jar file

Need a quick hand...little bit of a rush here.
How do I go about instantiating a class from a jar file?
If my jar file resides at c:/MyApp/MyJar.jar
The contents of the jar file are:
meta-inf/MANIFEST.MF
A.java
How do I go about creating an instance of A? I see people saying to use the URLClassLoader, but I can't find any good sample code to clarify how it's done. Assuming I already know the name of the class I'm instantiating, could someone show me how the URLClassLoader is used please? Also, please note that the jar file is NOT in my classpath, and I am not able to put it there....because it needs to be dynamically loaded as a plugin. I'm not sure if that matters or not with regards to the instantiation.

Thanks so much for that..I think it's just about what I need. However, I'm still running into a bit of a snag. After executing the code and trying to run a method to print something out from the object I just loaded, it instead prints a memory location. So I don't think it is quite working as intended. Here's the code I'm working with at the moment....
String jarPath = baseDir + "myApp/plugins/" + fileName;
Manifest mf = jar.getManifest();
Attributes att = mf.getMainAttributes();
String className = att.getValue("Main-Class");
//System.out.println(className);
File file = new File(jarPath);
URL[] urls = new URL[] {file.toURL()};
ClassLoader loader = URLClassLoader.newInstance(urls);
Class dynmicallyLoadedClass = Class.forName(className, true, loader);
PlugIn plugin = (PlugIn) dynmicallyLoadedClass.newInstance();
System.out.println(plugin.toString()); //This prints out "TMGImporter@1ce50a9" instead of what it's supposed to....Also, I am using Java 1.4.2_08 so I can't use generics. There are no error messages, just the wrong output. The jar this is using actually contains two files, besides the manifest. The TMGImporter (which Im trying to instantiate) and a TMGImporter$1 anonymous inner class. There is no package declaration on the class.
Any thoughts?

How to get resources from jar-files

Hi
in my app I load an image via the Toolkit.getImage() method.
Works fine if the app and the image are in folders on disk.
It fails to load the image, if the app (and the image) is packed in a jar file.
How can I get the image from there?
I try to get the image as follows:
String s = getClass().getResource("MyApp.class").getFile();
AppPath = s.substring(0,s.lastIndexOf("/"));
String PathToImages = "/images";
MyImage = (Image)Toolkit.getDefaultToolkit().getImage(AppPath+PathToImages+"/logo32.gif");The App starts and works, it just fails to load the images.
Any solutions??
thanx in advance
Herby

This is actually pretty easy. First a little background.
A Jar file is just a Zip file, with a few constructs for Java.
The getResource() method is used to create a mapping to data within the Jar file, but is actually not necessary after you know how the mapping works.
Just to give you an example of getResource:
// returned is a url to the resource you want from your Jar file.
URL myURL = MyClass.class.getResource("images/myimgage.gif");
// then you can use this URL to load the resource
Image img = getImage(myURL);If you were you look at the value of myURL you would see something similar to the followiing.
jar:http://www.mywebsite.com/mydir/myjarfile.jar!/images/myimage.gifJust to break it down for you.
The line always starts with the word jar:
Followed by the path to your jar file.
A sepearator !/
Then the file you are loading from the Jar file.
jar: path_to_jar_file !/ path_to_resource_in_jar_fileSo if you'd like, you could just create a URL object, and define the path to the object using the above method rather than using getResource.
Anyway, back to your code. What I would do is print out what you get for:AppPath+PathToImages+"/logo32.gif"I'm thinking you might be getting 2 "/" in your path because I think:AppPath = s.substring(0,s.lastIndexOf("/"));will leave the "/" at the end and the next line you add the "/" in front of the image directory name. So you my have the following for your image path.mypath//images

Loading icons from jar file

Hello,
i am trying to load ALL imagefiles from my jar file. i do the following:
Class clazz = Class.forName("com.xxx.IconSelectionDialog");
String me = clazz.getName().replace(".", "/") + ".class";
dirURL = clazz.getClassLoader().getResource(me);
if (dirURL.getProtocol().equals("jar")) {
String jarPath = dirURL.getPath().substring(6, dirURL.getPath().indexOf("!")); //strip out only the JAR file
JarFile jar = new JarFile(jarPath );
Enumeration<JarEntry> entries = jar.entries(); //gives ALL entries in jar
while (entries.hasMoreElements()) {
JarEntry nextEntry = entries.nextElement();
String jarEntryName = nextEntry.getName();
this works fine with my debug local jws installation. when i try to run it online starting i get an error:
java.io.FileNotFoundException: xentis.jar (Das System kann die angegebene Datei nicht finden)
     at java.util.zip.ZipFile.open(Native Method)
     at java.util.zip.ZipFile.<init>(ZipFile.java:114)
     at java.util.jar.JarFile.<init>(JarFile.java:133)
     at java.util.jar.JarFile.<init>(JarFile.java:70)
how can i load ALL icons from a jar (without knowing the filename) ?
is there a generic way to iterate over all entries of a jarfile ?
thank you
michael

Look at "Loading Images Using getResource" on this page
http://java.sun.com/docs/books/tutorial/uiswing/components/icon.html
It should provide some ideas.

How to load class from jar file dynamically?

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