Loading resource bundles in Java from property files outside of classpath, with different file extensions.

app.java

package com.cpm;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Locale;
import java.util.PropertyResourceBundle;
import java.util.ResourceBundle;

//ref: http://stackoverflow.com/questions/1172424/how-to-load-a-resource-bundle-from-a-file-resource-in-java
public class App {

    public static void main(String[] args) throws IOException {
        String currentDir = System.getProperty("user.dir");
        System.out.println("Working Directory = " + currentDir);

        ResourceBundle rb = fromClassLoader(currentDir, "test");
        System.out.println("From bundle: key one = " + rb.getString("one"));

        ResourceBundle rb2 = fromFile(currentDir, "test.pro");
        System.out.println("From file: key one = " + rb2.getString("one"));
    }

    private static ResourceBundle fromClassLoader(String dir, String bundleName) throws MalformedURLException {
        File file = new File(dir);
        URL[] urls = {file.toURI().toURL()};
        ClassLoader loader = new URLClassLoader(urls);
        // Properties file name = test.properties. The .properties extension is appended to bundle name
        return ResourceBundle.getBundle(bundleName, Locale.getDefault(), loader);
    }

    //This method doesn't use localization
    private static ResourceBundle fromFile(String dir, String fileName) throws IOException {
        FileInputStream fis = new FileInputStream(dir + "/" + fileName);
        try {
            return new PropertyResourceBundle(fis);
        } finally {
            fis.close();
        }
    }
}