With the directory on the classpath, from a class loaded by the same classloader, you should be able to use either of:

// From ClassLoader, all paths are "absolute" already - there's no context
// from which they could be relative. Therefore you don't need a leading slash.
InputStream in = this.getClass().getClassLoader()
                                .getResourceAsStream("SomeTextFile.txt");
// From Class, the path is relative to the package of the class unless
// you include a leading slash, so if you don't want to use the current
// package, include a slash like this:
InputStream in = this.getClass().getResourceAsStream("/SomeTextFile.txt");

If those aren't working, that suggests something else is wrong.

So for example, take this code:

package dummy;

import java.io.*;

public class Test
{
    public static void main(String[] args)
    {
        InputStream stream = Test.class.getResourceAsStream("/SomeTextFile.txt");
        System.out.println(stream != null);
        stream = Test.class.getClassLoader().getResourceAsStream("SomeTextFile.txt");
        System.out.println(stream != null);
    }
}

And this directory structure:

code
    dummy
          Test.class
txt
    SomeTextFile.txt

And then (using the Unix path separator as I'm on a Linux box):

java -classpath code:txt dummy.Test

Results:

true
true

Try getting hold of a URL for your classpath resource:

URL url = this.getClass().getResource("/com/path/to/file.txt")

Then create a file using the constructor that accepts a URI:

File file = new File(url.toURI());

You are not passing the image data to the file!! You're trying to write an empty file in the path of the image!!

I would recommend our Apache friends FileUtils library (getting classpath as this answer):

import org.apache.commons.io.FileUtils

URL url = getClass().getResource("src/image.jpg");
final File f = new File(MyClass.class.getProtectionDomain().getCodeSource().getLocation().getPath());
FileUtils.copyURLToFile(url, f);

This method downloads the url, and save it to file f.

You can only add folders or jar files to a class loader. So if you have a single class file, you need to put it into the appropriate folder structure first.

Here is a rather ugly hack that adds to the SystemClassLoader at runtime:

import java.io.IOException;
import java.io.File;
import java.net.URLClassLoader;
import java.net.URL;
import java.lang.reflect.Method;

public class ClassPathHacker {

  private static final Class[] parameters = new Class[]{URL.class};

  public static void addFile(String s) throws IOException {
    File f = new File(s);
    addFile(f);
  }//end method

  public static void addFile(File f) throws IOException {
    addURL(f.toURL());
  }//end method


  public static void addURL(URL u) throws IOException {

    URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
    Class sysclass = URLClassLoader.class;

    try {
      Method method = sysclass.getDeclaredMethod("addURL", parameters);
      method.setAccessible(true);
      method.invoke(sysloader, new Object[]{u});
    } catch (Throwable t) {
      t.printStackTrace();
      throw new IOException("Error, could not add URL to system classloader");
    }//end try catch

   }//end method

}//end class

The reflection is necessary to access the protected method addURL. This could fail if there is a SecurityManager.

Use ClassLoader#getResource() or getResourceAsStream() to obtain them as URL or InputStream from the classpath.

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("com/example/file.ext");
// ...

Or if it is in the same package as the current class, you can also obtain it as follows:

InputStream input = getClass().getResourceAsStream("file.ext");
// ...

Saving is a story apart. This won't work if the file is located in a JAR file. If you can ensure that the file is expanded and is writable, then convert the URL from getResource() to File.

URL url = classLoader.getResource("com/example/file.ext");
File file = new File(url.toURI().getPath());
// ...

You can then construct a FileOutputStream with it.

Related questions:

• getResourceAsStream() versus FileInputStream

Instead of trying to get the class path name, Create a File object and then get its absolute path using the getAbsolutePath() method. This will give the path of the source file which runs the code.

Kindly try the below code:-

 java.io.File f = new java.io.File("H");
        String path;
        path = f.getAbsolutePath();
        path = path.substring(0, (path.length() - f.getName().length()));
        f.deleteOnExit();

where the string path will then contain your class file directory path.