Develop Reference

windows - User folder with special character -> class.getResource returns null [duplicate]

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.

Modify the feet to meters program to read from, write to a file. The input file named “feet.txt” and the output file “meters.txt” [duplicate]

I have an assignment for my CS class where it says to read a file with several test scores and asks me to sum and average them. While summing and averaging is easy, I am having problems with the file reading. The instructor said to use this syntax
Scanner scores = new Scanner(new File("scores.dat"));
However, this throws a FileNotFoundException, but I have checked over and over again to see if the file exists in the current folder, and after that, I figured that it had to do something with the permissions. I changed the permissions for read and write for everyone, but it still did not work and it still keeps throwing the error. Does anyone have any idea why this may be occurring?
EDIT: It was actually pointing to a directory up, however, I have fixed that problem. Now file.exists() returns true, but when I try to put it in the Scanner, it throws the FileNotFoundException
Here is all my code
import java.util.Scanner;
import java.io.*;
public class readInt{
public static void main(String args[]){
File file = new File("lines.txt");
System.out.println(file.exists());
Scanner scan = new Scanner(file);
}
}

There are a number situation where a FileNotFoundException may be thrown at runtime.
The named file does not exist. This could be for a number of reasons including:
The pathname is simply wrong
The pathname looks correct but is actually wrong because it contains non-printing characters (or homoglyphs) that you did not notice
The pathname is relative, and it doesn't resolve correctly relative to the actual current directory of the running application. This typically happens because the application's current directory is not what you are expecting or assuming.
The path to the file is is broken; e.g. a directory name of the path is incorrect, a symbolic link on the path is broken, or there is a permission problem with one of the path components.
The named file is actually a directory.
The named file cannot be opened for reading for some reason.
The good news that, the problem will inevitably be one of the above. It is just a matter of working out which. Here are some things that you can try:
Calling file.exists() will tell you if any file system object exists with the given name / pathname.
Calling file.isDirectory() will test if it is a directory.
Calling file.canRead() will test if it is a readable file.
This line will tell you what the current directory is:
System.out.println(new File(".").getAbsolutePath());
This line will print out the pathname in a way that makes it easier to spot things like unexpected leading or trailing whitespace:
System.out.println("The path is '" + path + "'");
Look for unexpected spaces, line breaks, etc in the output.
It turns out that your example code has a compilation error.
I ran your code without taking care of the complaint from Netbeans, only to get the following exception message:
Exception in thread "main" java.lang.RuntimeException: Uncompilable
source code - unreported exception java.io.FileNotFoundException; must
be caught or declared to be thrown
If you change your code to the following, it will fix that problem.
public static void main(String[] args) throws FileNotFoundException {
File file = new File("scores.dat");
System.out.println(file.exists());
Scanner scan = new Scanner(file);
}
Explanation: the Scanner(File) constructor is declared as throwing the FileNotFoundException exception. (It happens the scanner it cannot open the file.) Now FileNotFoundException is a checked exception. That means that a method in which the exception may be thrown must either catch the exception or declare it in the throws clause. The above fix takes the latter approach.

The code itself is working correctly. The problem is, that the program working path is pointing to other place than you think.
Use this line and see where the path is:
System.out.println(new File(".").getAbsoluteFile());

Obviously there are a number of possible causes and the previous answers document them well, but here's how I solved this for in one particular case:
A student of mine had this problem and I nearly tore my hair out trying to figure it out. It turned out that the file didn't exist, even though it looked like it did. The problem was that Windows 7 was configured to "Hide file extensions for known file types." This means that if file appears to have the name "data.txt" its actual filename is "data.txt.txt".
Hope this helps others save themselves some hair.

I recently found interesting case that produces FileNotFoundExeption when file is obviously exists on the disk.
In my program I read file path from another text file and create File object:
//String path was read from file
System.out.println(path); //file with exactly same visible path exists on disk
File file = new File(path);
System.out.println(file.exists()); //false
System.out.println(file.canRead()); //false
FileInputStream fis = new FileInputStream(file); // FileNotFoundExeption
The cause of the problem was that the path contained invisible \r\n characters at the end.
The fix in my case was:
File file = new File(path.trim());
To generalize a bit, the invisible / non-printing characters could have include space or tab characters, and possibly others, and they could have appeared at the beginning of the path, at the end, or embedded in the path. Trim will work in some cases but not all. There are a couple of things that you can help to spot this kind of problem:
Output the pathname with quote characters around it; e.g.
System.out.println("Check me! '" + path + "'");
and carefully check the output for spaces and line breaks where they shouldn't be.
Use a Java debugger to carefully examine the pathname string, character by character, looking for characters that shouldn't be there. (Also check for homoglyph characters!)

An easy fix, which worked for me, is moving my files out of src and into the main folder of the project. It's not the best solution, but depending on the magnitude of the project and your time, it might be just perfect.

Reading and writing from and to a file can be blocked by your OS depending on the file's permission attributes.
If you are trying to read from the file, then I recommend using File's setReadable method to set it to true, or, this code for instance:
String arbitrary_path = "C:/Users/Username/Blah.txt";
byte[] data_of_file;
File f = new File(arbitrary_path);
f.setReadable(true);
data_of_file = Files.readAllBytes(f);
f.setReadable(false); // do this if you want to prevent un-knowledgeable
//programmers from accessing your file.
If you are trying to write to the file, then I recommend using File's setWritable method to set it to true, or, this code for instance:
String arbitrary_path = "C:/Users/Username/Blah.txt";
byte[] data_of_file = { (byte) 0x00, (byte) 0xFF, (byte) 0xEE };
File f = new File(arbitrary_path);
f.setWritable(true);
Files.write(f, byte_array);
f.setWritable(false); // do this if you want to prevent un-knowledgeable
//programmers from changing your file (for security.)

Apart from all the other answers mentioned here, you can do one thing which worked for me.
If you are reading the path through Scanner or through command line args, instead of copy pasting the path directly from Windows Explorer just manually type in the path.
It worked for me, hope it helps someone :)

I had this same error and solved it simply by adding the src directory that is found in Java project structure.
String path = System.getProperty("user.dir") + "\\src\\package_name\\file_name";
File file = new File(path);
Scanner scanner = new Scanner(file);
Notice that System.getProperty("user.dir") and new File(".").getAbsolutePath() return your project root directory path, so you have to add the path to your subdirectories and packages

You'd obviously figure it out after a while but just posting this so that it might help someone. This could also happen when your file path contains any whitespace appended or prepended to it.

Use single forward slash and always type the path manually. For example:
FileInputStream fi= new FileInputStream("D:/excelfiles/myxcel.xlsx");

What worked for me was catching the exception. Without it the compiler complains even if the file exists.
InputStream file = new FileInputStream("filename");
changed to
try{
InputStream file = new FileInputStream("filename");
System.out.println(file.available());
}
catch (Exception e){
System.out.println(e);
}

This works for me. It also can read files such txt, csv and .in
public class NewReader {
public void read() throws FileNotFoundException, URISyntaxException {
File file = new File(Objects.requireNonNull(NewReader.class.getResource("/test.txt")).toURI());
Scanner sc = new Scanner(file);
while (sc.hasNext()) {
String text = sc.next();
System.out.println(text);
}
}
}
the file is located in resource folder generated by maven. If you have other folders nested in, just add it to the file name like "examples/test.txt".

Output of Reading the file is not getting as Expected? [duplicate]

I have an assignment for my CS class where it says to read a file with several test scores and asks me to sum and average them. While summing and averaging is easy, I am having problems with the file reading. The instructor said to use this syntax
Scanner scores = new Scanner(new File("scores.dat"));
However, this throws a FileNotFoundException, but I have checked over and over again to see if the file exists in the current folder, and after that, I figured that it had to do something with the permissions. I changed the permissions for read and write for everyone, but it still did not work and it still keeps throwing the error. Does anyone have any idea why this may be occurring?
EDIT: It was actually pointing to a directory up, however, I have fixed that problem. Now file.exists() returns true, but when I try to put it in the Scanner, it throws the FileNotFoundException
Here is all my code
import java.util.Scanner;
import java.io.*;
public class readInt{
public static void main(String args[]){
File file = new File("lines.txt");
System.out.println(file.exists());
Scanner scan = new Scanner(file);
}
}

There are a number situation where a FileNotFoundException may be thrown at runtime.
The named file does not exist. This could be for a number of reasons including:
The pathname is simply wrong
The pathname looks correct but is actually wrong because it contains non-printing characters (or homoglyphs) that you did not notice
The pathname is relative, and it doesn't resolve correctly relative to the actual current directory of the running application. This typically happens because the application's current directory is not what you are expecting or assuming.
The path to the file is is broken; e.g. a directory name of the path is incorrect, a symbolic link on the path is broken, or there is a permission problem with one of the path components.
The named file is actually a directory.
The named file cannot be opened for reading for some reason.
The good news that, the problem will inevitably be one of the above. It is just a matter of working out which. Here are some things that you can try:
Calling file.exists() will tell you if any file system object exists with the given name / pathname.
Calling file.isDirectory() will test if it is a directory.
Calling file.canRead() will test if it is a readable file.
This line will tell you what the current directory is:
System.out.println(new File(".").getAbsolutePath());
This line will print out the pathname in a way that makes it easier to spot things like unexpected leading or trailing whitespace:
System.out.println("The path is '" + path + "'");
Look for unexpected spaces, line breaks, etc in the output.
It turns out that your example code has a compilation error.
I ran your code without taking care of the complaint from Netbeans, only to get the following exception message:
Exception in thread "main" java.lang.RuntimeException: Uncompilable
source code - unreported exception java.io.FileNotFoundException; must
be caught or declared to be thrown
If you change your code to the following, it will fix that problem.
public static void main(String[] args) throws FileNotFoundException {
File file = new File("scores.dat");
System.out.println(file.exists());
Scanner scan = new Scanner(file);
}
Explanation: the Scanner(File) constructor is declared as throwing the FileNotFoundException exception. (It happens the scanner it cannot open the file.) Now FileNotFoundException is a checked exception. That means that a method in which the exception may be thrown must either catch the exception or declare it in the throws clause. The above fix takes the latter approach.

The code itself is working correctly. The problem is, that the program working path is pointing to other place than you think.
Use this line and see where the path is:
System.out.println(new File(".").getAbsoluteFile());

Obviously there are a number of possible causes and the previous answers document them well, but here's how I solved this for in one particular case:
A student of mine had this problem and I nearly tore my hair out trying to figure it out. It turned out that the file didn't exist, even though it looked like it did. The problem was that Windows 7 was configured to "Hide file extensions for known file types." This means that if file appears to have the name "data.txt" its actual filename is "data.txt.txt".
Hope this helps others save themselves some hair.

I recently found interesting case that produces FileNotFoundExeption when file is obviously exists on the disk.
In my program I read file path from another text file and create File object:
//String path was read from file
System.out.println(path); //file with exactly same visible path exists on disk
File file = new File(path);
System.out.println(file.exists()); //false
System.out.println(file.canRead()); //false
FileInputStream fis = new FileInputStream(file); // FileNotFoundExeption
The cause of the problem was that the path contained invisible \r\n characters at the end.
The fix in my case was:
File file = new File(path.trim());
To generalize a bit, the invisible / non-printing characters could have include space or tab characters, and possibly others, and they could have appeared at the beginning of the path, at the end, or embedded in the path. Trim will work in some cases but not all. There are a couple of things that you can help to spot this kind of problem:
Output the pathname with quote characters around it; e.g.
System.out.println("Check me! '" + path + "'");
and carefully check the output for spaces and line breaks where they shouldn't be.
Use a Java debugger to carefully examine the pathname string, character by character, looking for characters that shouldn't be there. (Also check for homoglyph characters!)

An easy fix, which worked for me, is moving my files out of src and into the main folder of the project. It's not the best solution, but depending on the magnitude of the project and your time, it might be just perfect.

Reading and writing from and to a file can be blocked by your OS depending on the file's permission attributes.
If you are trying to read from the file, then I recommend using File's setReadable method to set it to true, or, this code for instance:
String arbitrary_path = "C:/Users/Username/Blah.txt";
byte[] data_of_file;
File f = new File(arbitrary_path);
f.setReadable(true);
data_of_file = Files.readAllBytes(f);
f.setReadable(false); // do this if you want to prevent un-knowledgeable
//programmers from accessing your file.
If you are trying to write to the file, then I recommend using File's setWritable method to set it to true, or, this code for instance:
String arbitrary_path = "C:/Users/Username/Blah.txt";
byte[] data_of_file = { (byte) 0x00, (byte) 0xFF, (byte) 0xEE };
File f = new File(arbitrary_path);
f.setWritable(true);
Files.write(f, byte_array);
f.setWritable(false); // do this if you want to prevent un-knowledgeable
//programmers from changing your file (for security.)

Apart from all the other answers mentioned here, you can do one thing which worked for me.
If you are reading the path through Scanner or through command line args, instead of copy pasting the path directly from Windows Explorer just manually type in the path.
It worked for me, hope it helps someone :)

I had this same error and solved it simply by adding the src directory that is found in Java project structure.
String path = System.getProperty("user.dir") + "\\src\\package_name\\file_name";
File file = new File(path);
Scanner scanner = new Scanner(file);
Notice that System.getProperty("user.dir") and new File(".").getAbsolutePath() return your project root directory path, so you have to add the path to your subdirectories and packages

You'd obviously figure it out after a while but just posting this so that it might help someone. This could also happen when your file path contains any whitespace appended or prepended to it.

Use single forward slash and always type the path manually. For example:
FileInputStream fi= new FileInputStream("D:/excelfiles/myxcel.xlsx");

What worked for me was catching the exception. Without it the compiler complains even if the file exists.
InputStream file = new FileInputStream("filename");
changed to
try{
InputStream file = new FileInputStream("filename");
System.out.println(file.available());
}
catch (Exception e){
System.out.println(e);
}

This works for me. It also can read files such txt, csv and .in
public class NewReader {
public void read() throws FileNotFoundException, URISyntaxException {
File file = new File(Objects.requireNonNull(NewReader.class.getResource("/test.txt")).toURI());
Scanner sc = new Scanner(file);
while (sc.hasNext()) {
String text = sc.next();
System.out.println(text);
}
}
}
the file is located in resource folder generated by maven. If you have other folders nested in, just add it to the file name like "examples/test.txt".

Where is the file stored to be read by FileInputStream?

I'm getting 'File not found!' no matter what I do.
FileInputStream fin;
try {
fin = new FileInputStream("foo.txt");
String str = IOUtils.toString(fin);
System.out.println(str);
} catch (FileNotFoundException f) {
System.out.println("File not found!");
}

Do you have a foo.txt in the directory that you are working in?.
If you are using command window and are at a location say, C:\, then your code expects foo.txt to be present there.
If your foo.txt is present in some other path, use the full path in your code.

If you temporarily add this line to your code:
System.out.println(new File("foo.txt").getAbsolutePath());
it should tell you where it expects to find the file. If the file isn't in that location, then you'll either have to specify the path or move the file so that it is.

Make sure you're using the correct path. Try right-clicking and go on to Properties and check the file's path. Copy and paste the path and replace all the \ to either / or \\.

unable to findright file path

I am facing some problem to fix the right file path.
I have a configuration file and following is the entry in config.properties:
strMasterTestSuiteFilePath="D:\\KeywordDrivenFramework\\MasterTestSuiteFile.xls"
Then i tried to read this property as
Properties prop=new Properties();
prop.load("config.properties")
String strpath=prop.getProperty("strMasterTestSuiteFilePath")
Syso(strpath) //prints above path with single slash as D:\KeywordDrivenFramework\MasterTestSuiteFile.xls
//When i use the same var for File existance check it say not exists
File obj=new File(strpath)
if(obj.exists())
Syso("Exists....")
else
Syso("Does not exist....")
Why it is going to else block, even though the file exists at path?
How to overcome it?
I tried
String str= strpath.replaceAll("\","\\") //but i am getting some syntax error "The method replaceAll(String, String) in the type String is not applicable for the arguments (String)"
Can anyone help me how to overcome this?
Find the code which i am trying, where i am going wrong?
public void LoadMasterTestSuite()
{
String strGlobalConfigSettingFilePath=System.getProperty("user.dir")+"/src/GlobalConfigurationSettings.properties";
FileInputStream objFIS; //Variable to hold FileSystem Objet
File objFile; //Variable to hold File Object
try
{
objFIS = new FileInputStream(new File(strGlobalConfigSettingFilePath));
globalObjProp.load(objFIS);
strMasterTSFilePath=globalObjProp.getProperty("strMasterTestSuiteFilePath");
objAppLog.info("Master Test Suite File Path configured as "+strMasterTSFilePath);
}catch (FileNotFoundException e)
{
objAppLog.info("Unable to find Global Configuration Settings File. So aborting...");
e.printStackTrace();
}catch (IOException e)
{
e.printStackTrace();
}
String str=strMasterTSFilePath.replace("\\", "\\\\");
objFile=new File(str);
System.out.println(str);
if(objFile.exists())
{
LoadTestSuite(strMasterTSFilePath);
}
else
{
objAppLog.info("Master Test Suite File not found at Path: "+strMasterTSFilePath);
System.exit(-1);
}
}

I guess what you wanted to do was:
String str= strpath.replaceAll("\\\\","\\")
\ is a special character in a String. To Treat it like a normal character, put another \ in front of it, so '\' actually is '\\'.
And for your case, I think you want to use .replace() and not .replaceAll().

When you debug, is strpath getting the correct path from the config file? I would also make sure that you're referencing the correct file path (paste the location into Windows Explorer and see if the file exists). If D:\ is a shared drive, use the actual server location.
Also, you can make sure that the extension of the Excel workbook is .xls and not .xlsx.