properties file resides outside of the java app throws fFileNotFoundException

Question

For some reason i have to place my *.properties files outside of java app. When the file km.properties resides in java/src/resources/km.properties the code reads the file but when i place the same file in C:\Users\abc\Desktop\km.properties it throws

Exception: java.io.FileNotFoundException: property file 'C:\Users\abc\Desktop\km.properties' not found in the classpath
Exception in thread "main" java.lang.NullPointerException
    at com.ir.Constants.<init>(Constants.java:44)
    at com.Constants.main(Constants.java:64)

here is my code

public class Constants {
    public Constants(){
        System.out.println(System.getenv("km_config"));
        try {
            Properties prop = new Properties();
            String propFileName = System.getenv("km_config");

            inputStream = getClass().getClassLoader().getResourceAsStream(propFileName);

            if (inputStream != null) {
                prop.load(inputStream);
            } else {
                throw new FileNotFoundException("property file '" + propFileName + "' not found in the classpath");
            }
        }
        catch (IOException e) {
            System.out.println("Exception: " + e);
        }
        catch (Exception e) {
            System.out.println("Exception: " + e);
        } finally {
            try {
                inputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }


    }

public static void main(String[] args) throws Exception {
        Constants c = new Constants();

         System.out.println(Constants.DB_PATH1);
         System.out.println(Constants.GIT_REPO_PATH);
         System.out.println(Constants.GIT_MAIN_BRANCH_NAME);
         System.out.println(Constants.TAGGER_PATH);
    }

Constants.java:44 is inputStream.close();

Constants.java:64 is Constants c = new Constants();

please help me i need to place km.properies file any where outside of the java app

command results in

echo %km_config%

C:\Users\abc\Desktop\km.properties

Answer 1

The API ClassLoader::getResourceAsStream(String) has a search path which is the classpath. Actually you are right that the configuration file should not be bundled with your .class files and read from the filesystem of the target machine instead.

Thus your API call becomes:

Properties conf = new Properties();
conf.load(new InputStreamReader(new FileInputStream(new File(file)));

_{Note: I did not specify a charset for converting the stream of bytes to a stream of character because I want the JVM to pick whatever character is the default for the system.}

For testing I suggest you:

• put the configuration file in a known location out of the sources (the Desktop) or anyway ignored by the version control system
• pass the value as a system property (like -Dfile=C:\Users\me\Desktop\km.properties)