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In what situation is a file placed in the resources of a JAR, but is not accessible in a class' ClassLoader?

I'm just trying to read in a simple .txt file into my java project using this.class.getResourceAsStream(filename). I have several files within main/resources, and almost all of them return an object when I try to get them as an input stream. The only object I can't read in is my text file.
I have placed the file with all of the other resource files that are readable by the classloader, but it appears this file wasn't placed in the class' classLoader for whatever reason. If I unzip the jar, the file is still included with the jar in the same directory as all of the other resources, so it seems to be being built correctly.
I guess what I'm asking is at what point do I tell Java what files I want to be included as a resource in a class' ClassLoader? Is it something that should be done when the jar is built if things are in the correct place (i.e main/resources)?
Here is what the code looks like, and it's respective return values, when running for the file it can find and the file it can't, that are both located in the same place.
// This is not found. Both are placed at src/main/resources
def tmpDict = this.class.getResourceAsStream("dict.txt")
println tmpDict // null
// This is found
def tmpDict2 = this.class.getResourceAsStream("calc.config")
println tmpDict2 // sun.net.www.protocol.jar.JarURLConnection$JarURLInputStream#2dae5a79

Without more info i'd say the path is wrong. when i used just "file.txt" for the path it got NPE
i used this method to read from the stream. The file was located at \src\main\resources\static\file.txt
This worked in eclipse, packaged into jar and worked there too.
public String getFile() throws Exception {
InputStream in = Controller.class.getClassLoader().getResourceAsStream("static/file.txt");
BufferedReader reader = new BufferedReader(new InputStreamReader(in, Charset.defaultCharset()));
StringBuilder out = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
out.append(line);
}
return out.toString();
}

Some very Basic checks:
The file must be case-sensitive (as it is not a Windows file), and special characters of the file name might be cumbersome. Also check that the file in your project has the file extension not twice (.txt.txt - Windows hiding the extension).
Check that getResourceAsStream("/a/b/c/A.txt") indeed gives a null.
If not the reading might go wrong on the encoding.

How do I get path with spaces to current executing jar with java command in Linux?

I have two methods to obtain the jar path
1)
File file = new File(new File(Main.class.getProtectionDomain().getCodeSource().getLocation().getPath()).getName());
String filename = file.getAbsolutePath().toString();
2)
String filename2 = Main.class.getProtectionDomain().getCodeSource().getLocation().toString().substring(6);
The first method works perfectly for windows and Mac, but in linux, if my jar is located at '/home/user/Documents/test folder/', it returns my current working directory + the jar file
Ex: If my terminal is at /home/user/, it returns /home/user/MyJar.jar even though MyJar.jar path is '/home/user/Documents/test folder/'.
The second method, for every operational system returns the correct path to the file but with spaces replaced by %20.
Ex: /home/user/Documents/test%20folder/MyJar.jar
How can I get the absolute path in Linux the same way I do for windows and Mac, and without %20 as space replacement?

I'm not sure why you've double wrapped your File's in the first solution.
try {
File f = new File(Main.class.getProtectionDomain().getCodeSource().getLocation().toURI());
System.out.println(f.getAbsolutePath());
} catch (URISyntaxException ex) {
throw new RuntimeException(ex);
}
(Only tested under Linux)
(I don't think the URISyntaxException will ever be thrown in production)

In Java, why does class.getResource("/path/to/res"); not work in the runnable jar when copying files to the system?

I have been working on a project that requires the user to "install" the program upon running it the first time. This installation needs to copy all the resources from my "res" folder to a dedicated directory on the user's hard drive. I have the following chunk of code that was working perfectly fine, but when I export the runnable jar from eclipse, I received a stack trace which indicated that the InputStream was null. The install loop passes the path of each file in the array list to the export function, which is where the issue is (with the InputStream). The paths are being passed correctly in both Eclipse and the runnable jar, so I doubt that is the issue. I have done my research and found other questions like this, but none of the suggested fixes (using a classloader, etc) have worked. I don't understand why the method I have now works in Eclipse but not in the jar?
(There also exists an ArrayList of File called installFiles)
private static String installFilesLocationOnDisk=System.getProperty("user.home")+"/Documents/[project name]/Resources/";
public static boolean tryInstall(){
for(File file:installFiles){
//for each file, make the required directories for its extraction location
new File(file.getParent()).mkdirs();
try {
//export the file from the jar to the system
exportResource("/"+file.getPath().substring(installFilesLocationOnDisk.length()));
} catch (Exception e) {
return false;
}
}
return true;
}
private static void exportResource(String resourceName) throws Exception {
InputStream resourcesInputStream = null;
OutputStream resourcesOutputStream = null;
//the output location for exported files
String outputLocation = new File(installFilesLocationOnDisk).getPath().replace('\\', '/');
try {
//This is where the issue arises when the jar is exported and ran.
resourcesInputStream = InstallFiles.class.getResourceAsStream(resourceName);
if(resourcesInputStream == null){
throw new Exception("Cannot get resource \"" + resourceName + "\" from Jar file.");
}
//Write the data from jar's resource to system file
int readBytes;
byte[] buffer = new byte[4096];
resourcesOutputStream = new FileOutputStream(outputLocation + resourceName);
while ((readBytes = resourcesInputStream.read(buffer)) > 0) {
resourcesOutputStream.write(buffer, 0, readBytes);
}
} catch (Exception ex) {
ex.printStackTrace();
System.exit(1);
} finally {
//Close streams
resourcesInputStream.close();
resourcesOutputStream.close();
}
}
Stack Trace:
java.lang.Exception: Cannot get resource "/textures\gameIcon.png" from Jar file.
All help is appreciated! Thanks

Stack Trace:
java.lang.Exception: Cannot get resource "/textures\gameIcon.png" from Jar file.
The name if the resource is wrong. As the Javadoc of ClassLoader.getResource(String) describes (and Class.getResourceAsStream(String) refers to ClassLoader for details):
The name of a resource is a /-separated path name that identifies
the resource.
No matter whether you get your resources from the File system or from a Jar File, you should always use / as the separator.
Using \ may sometimes work, and sometimes not: there's no guarantee. But it's always an error.
In your case, the solution is a change in the way that you invoke exportResource:
String path = file.getPath().substring(installFilesLocationOnDisk.length());
exportResource("/" + path.replace(File.pathSeparatorChar, '/'));

Rename your JAR file to ZIP, uncompress it and check where did resources go.
There is a possibility you're using Maven with Eclipse, and this means exporting Runnable JAR using Eclipse's functionality won't place resources in JAR properly (they'll end up under folder resources inside the JAR if you're using default Maven folder names conventions).
If that is the case, you should use Maven's Assembly Plugin (or a Shade plugin for "uber-JAR") to create your runnable JAR.
Even if you're not using Maven, you should check if the resources are placed correctly in the resulting JAR.
P.S. Also don't do this:
.getPath().replace('\\', '/');
And never rely on particular separator character - use java.io.File.separator to determine system's file separator character.

Unable to open resources in directories which end with an exclamation mark (!)

The getResourceAsStream-method returns null whenever running the executable jar in a directory which ends with a exclamation mark.
For the following example, I have a Eclipse project the following directory structure:
src\ (Source Folder)
main\ (Package)
Main.java
res\ (Source Folder)
images\
Logo.png
I'm reading the Logo.png as follows:
public static void main(String[] args) throws IOException {
try (InputStream is = Main.class.getClassLoader().getResourceAsStream("images/Logo.png")) {
Image image = ImageIO.read(is);
System.out.println(image);
}
}
See the attachment for 2 test cases. First, the executable jar is started from the directory "D:\test123!##" without any problems. Secondly, the executable jar is started from the directory "D:\test123!##!!!", with problems.
Are directories ending with an exclamation mark not supported? Is the code wrong?
Thanks in advance.

Probably because of this bug or any of the many similar bugs in the Java bug database:
http://bugs.sun.com/view_bug.do?bug_id=4523159
The reason is that "!/" in a jar URL is interpreted as the separator between the JAR file name and the path within the JAR itself. If a directory name ends with !, the "!/" character sequence at the end of the directory is incorrectly interpreted. In your case, you are actually trying to access a resource with the following URL:
jar:file:///d:/test1231##!!!/test.jar!/images/Logo.png
The bug has been open for almost 12 years and is not likely to be fixed. Actually I don't know how it can be fixed without breaking other things. The problem is the design decision to use ! as a character with a special meaning (separator) in the URL scheme for JAR files:
jar:<URL for JAR file>!/<path within the JAR file>
Since the exclamation mark is an allowed character in URLs, it may occur both in the URL to the JAR file itself, as well as in the path within the JAR file, making it impossible in some cases to find the actual "!/" separator.

A simple work around for Windows is to use "\" instead of "/" in the path. That would mean the "!/" character sequence is found after the full path. For instance:
new URL("jar:file:\\d:\\test1231##!!!\\test.jar!/images/Logo.png");
My Code:
File jar = new File(jarPath + "/" + jarName);
URL url = new URL("jar:" + jar.toURI() + "!" + dataFilePath);
InputStream stream = null;
try {
stream = url.openStream();
} catch (FileNotFoundException e) {
// Windows fix
URL urlFix = new URL("jar:" + jar.toURI().toString().replace('/', '\\')
+ "!" + dataFilePath);
stream = urlFix.openStream();
}
I use toURI() because it handles things like spaces.
Fixes:
The fix itself would be for Java to check if the file exists and if not continue to the next separator (the "!/" part of the url) until the separators are exhausted, then throw the exception. So it would see that "d:\test1231##!!" throws a java.io.FileNotFoundException and would then try "d:\test1231##!!!\test.jar" which does exist. This way it does not matter if there are "!" in the file path or in the jar's files.
Alternatively the "!/" can be switched to something else that is an illegal file name or to something specific (like "jarpath:").
Alternatively make the jar's file path use another parameter.
Note:
It may be possible to override something, swap a handler, or change the code to open the file first then look inside the jar file later but I have not looked.

Java: get absolute path of project

I'm trying to run a exe file in path outside of the current package. My code.java file that runs it is in
%Workspace_path%\Project\src\main\java\com\util\code.java
However the directory of where the exe is
%Workspace_path%\Project\src\main\resources\program.exe
If possible, it seems like the best solution here would be to get the absolute path of the Project then append "src\main\resources\" to it. Is there a good way to do this or is there an alternative solution?
I'm using Eclipse, but it would great if it could be used in other IDEs too. Thanks for any help.

The de facto approach to solving this is to bundle the EXE as a classpath resource. It seems you have arranged for this already.
When working with classpath resources, a mature program should not assume that the resource is in the filesystem. The resources could be packaged in a JAR file, or even in a WAR file. The only thing you can trust at that point is the standard methods for accessing resources in Java, as hinted below.
The way to solve your problem, then, is to access the resource contents using the de facto standard of invoking Class.getResourceAsStream (or ClassLoader.getResourceAsStream), save the contents to a temporary file, and execute from that file. This will guarantee your program works correctly regardless of its packaging.
In other words:
Invoke getClass().getResourceAsStream("/program.exe"). From static methods, you can't call getClass, so use the name of your current class instead, as in MyClass.class.getResourceAsStream. This returns an InputStream.
Create a temporary file, preferably using File.createTempFile. This returns a File object identifying the newly created file.
Open an OutputStream to this temp file.
Use the two streams to copy the data from the resource into the temp file. You can use IOUtils.copy if you're into Apache Commons tools. Don't forget to close the two streams when done with this step.
Execute the program thus stored in the temporary file.
Clean up.
In other words (code snippet added later):
private void executeProgramFromClasspath() throws IOException {
// Open resource stream.
InputStream input = getClass().getResourceAsStream("/program.exe");
if (input == null) {
throw new IllegalStateException("Missing classpath resource.");
}
// Transfer.
OutputStream output = null;
try {
// Create temporary file. May throw IOException.
File temporaryFile = File.createTempFile(getClass().getName(), "");
output = new FileOutputStream(temporaryFile);
output = new BufferedOutputStream(output);
IOUtils.copy(input, output);
} finally {
// Close streams.
IOUtils.closeQuietly(input);
IOUtils.closeQuietly(output);
}
// Execute.
try {
String path = temporaryFile.getAbsolutePath();
ProcessBuilder processBuilder = new ProcessBuilder(path);
Process process = processBuilder.start();
process.waitFor();
} catch (InterruptedException e) {
// Optional catch. Keeps the method signature uncluttered.
throw new IOException(e);
} finally {
// Clean up
if (!temporaryFile.delete()) {
// Log this issue, or throw an error.
}
}
}

Well,in your context,the project root is happen to be the current path
.
,that is where the java.exe start to execute,so a easy way is:
String exePath="src\\main\\resources\\program.exe";
File exeFile=new File(".",exePath);
System.out.println(exeFile.getAbusolutePath());
...
I tested this code on Eclipse,It's ok. I think is should work on different ide.
Good Luck!