Properties added to .jar not found

Question

I have a simple application of desktop. The aplication has a .jar, called MyApp.jar, of other aplication and in this jar there is a properties file with one key(infor.properties) . The aplication must generate a own MyApp.jar where the key of the properties file is the String in the inputText, so I must change que properties file. My problem is when I generate the new .jar, this jar doesn't find the properties file. I use this for get the content of infor.properties:

InputStream in = this.getClass().getClassLoader().getResourceAsStream("infor.properties");
Properties prop = new Properties();
prop.load(in);
in.close();

I use ZipFile and ZipOutputStream for copy every files to the new .jar, and add a new. The new structure of files the new .jar is correct, but when I run the new jar, doesn't find the file infor.properties. Does anyone know why?

Answer 1

It depends where is your file in the jar and how do you specify your class path. Unfortunately you did not give us much info on your structure etc. So I have created this sample which you hopefully can apply to yours project:

Lets say you have class Test in package testapp (full name of class is there fore testapp.Test ):

package testapp;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Test {

    private static final Logger logger = Logger.getLogger(Test.class.getName());

    public static void main(String[] args) {

            Properties properties = new Properties();
            try {
                properties.load(new FileInputStream("testapp/infor.properties"));
                System.out.println("" + properties.getProperty("a"));
            } catch (IOException e) {
                logger.log(Level.SEVERE, "", e);
            }

    }

}

You are in some directory PROJECT_ROOT. Now in this directory you have the above compiled class (in directory testapp, because your full name of the class is testapp.Test ). Your structure looks like this:

PROJECT_ROOT
  testapp
    Test.class
    infor.properties

Note, that the class is already compiled (you probably know how to do that right?). When your working dir is PROJECT_ROOT you can run:

 jar -vcf myjar.jar *

which will create a jar named myjar.jar . Now you can run the jar file using the following command

java -cp myjar.jar testapp.Test

which simply says (using -cp myjar.jar ) that the class path is myjar.jar (for JVM is the jar like directory).

As you could see in the Test.java you have "testapp/infor.properties" . The path to the property file must be specified in regard to used class path. The class path is the root of myjar.jar content. Therefore testapp/infor.properties.