Using the plus sign (+) in a file path exported to a jar file

Question

Hi,

The title might not be entirely clear, but I'll try to explain.

I'm trying to access a file with a path like /net/blm50+hmm/synlist/, which works fine when I don't export to a jar file and just run it from within my IDE (eclipse). However, if I try to run it when I have exported it, I get a null pointer exception. It runs without a problem if I rename the path to not have the plus sign in it. Can I escape the plus sign or something like that?

You might ask why I don't just rename the folder, and the reason for this is laziness. There is ALOT of folders to rename and I'd rather avoid it.

I hope You can help,

shalmon

EDIT:

I have a class FileUtils I use for accessing resources in the application jar:

public class FileUtils {

public static InputStream getInputStreamForResource(String resourcePath) throws IOException {
    // Try to get the file from the application jar first.
    InputStream result = FileUtils.class.getResourceAsStream(resourcePath);

    return result;
}

public static Scanner getScanner(String resourcePath) throws IOException {
    return new Scanner(getInputStreamForResource(resourcePath));
}

}

If I call getScanner("/net/blm50+hmm/synlist/"); I get the null pointer exception.

The stacktrace is (the call to getScanner happens in NetworkCollection.fromSynapseList):

java.lang.NullPointerException
    at java.io.Reader.<init>(Reader.java:61)
    at java.io.InputStreamReader.<init>(InputStreamReader.java:55)
    at java.util.Scanner.<init>(Scanner.java:590)
    at persistence.FileUtils.getScanner(FileUtils.java:34)
    at calculation.NetworkCollection.fromSynapseList(NetworkCollection.java:89)
    at processes.JobDispatcher.doInBackground(JobDispatcher.java:136)
    at processes.JobDispatcher.doInBackground(JobDispatcher.java:1)
    at javax.swing.SwingWorker$1.call(SwingWorker.java:277)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at javax.swing.SwingWorker.run(SwingWorker.java:316)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

Answer 1

For that code to work, the jar file must be available to the ClassLoader that loaded FileUtils (or simply, it should be on the classpath).

Answer 2

I once had a problem that could be somehow related: I got an exception when I tried to access a resource inside a jar file. Some code that worked with Java 1.4.2 but not with Java 1.6. At least I found a workaround...

Bet it's not a solution but maybe it's close enough to provide some help on your problem.

Answer 3

Try the following in your machine.

That is, create a file insulating the code that is failing and test it with a small subset of the input ( that is just one file, one with the + and one without it )

#create two folders: code and code+plus containing one file each
$ls -l code code+plus/ 
code:
total 8
-rw-r--r--  1 oscarreyes  staff  2 Jul  5 18:19 x

code+plus/:
total 8
-rw-r--r--  1 oscarreyes  staff  2 Jul  5 18:18 x

# create a sample with the code in question
$cat FileUtils.java 
import java.io.*;
import java.util.*;

public class FileUtils {

    public static InputStream getInputStreamForResource(String resourcePath) throws IOException {
        // Try to get the file from the application jar first.
        InputStream result = FileUtils.class.getResourceAsStream(resourcePath);
        return result;
    }

    public static Scanner getScanner(String resourcePath) throws IOException {
        return new Scanner(getInputStreamForResource(resourcePath));
    }
    public static void main( String [] args )  throws IOException {
        Scanner scanner = getScanner( args[0] );
        System.out.println( args[0] + " : OK");
    }

} 
#compile it
$javac FileUtils.java 

# package it with the subfodlers
$jar -cmf mf f.jar FileUtils.class  code+plus/ code 

# execute it without "+"
$java -jar f.jar /code/x 
/code/x : OK

#execute it with "+"
$java -jar f.jar /code+plus/x 
/code+plus/x : OK

#To get Npe, use a non existing file
$java -jar f.jar /code+plus/y 

Let me know if you still having the problem.

I'm pretty sure now your problem is while creating the jar file, you're now including the "+" file you think you're including.

To verify, run jar -tf your.jar and see if the file with + is listed.