Reloading the Properties form config file

Question

the doubt is on reloading the properties without restarting the server...
Earlier, I have a PropertyReader class which loads the properties from config file, here is the process I followed.
1)Calling the getInstance() from out side, which test the local instance variable exist or not, if it exists, then skip the creating new instance, else create the object by calling the self Constructor. Here is the method
   public static PropertyReader getInstance(String fileName) throws IOException{
        if (instance==null){
            try {
                instance = new PropertyReader(fileName);
            } catch (IOException e) {
                throw e;
        return instance;
    }2) In the Constructor, I read the properties from the property file like the following.
    Properties props = new Properties();
    InputStream fileIn = null;
    fileIn = getClass().getResourceAsStream("/" + "ldap.properties");
    props.load(fileIn);In this scenario I can't access the modified properties until I restart the server.
Now, I came to change the code to reload the properties with the following scenario.
1) in my getInstance method, I skip checking the instance and just calling new objct every time.
   public static PropertyReader getInstance(String fileName) throws IOException{
        return new PropertyReader(fileName);
    }2) Even after this, I can't access the latest properties, then I change the code in the Constructor like the following .
       URL codebase = getClass().getProtectionDomain().getCodeSource().getLocation();
            String subPath = codebase.getPath().substring(0, codebase.getPath().indexOf("WEB-INF")+16);
            file = new java.io.File(subPath+"ldap.properties");
            fileIn = new FileInputStream(file);
            props.load(fileIn);Here it is, now I'll be able to get the latest properties even without restarting the server.
So here I got couple of questions.
1) What if I create new instace everytime, will that cause any trouble in the memory point-of-view? i.e. load trouble?
2) What is the difference between 2 nd step in each scenario ? I can't get the exact difference.
Thanks,
Sumant K
Edited by: sumant14 on Jun 4, 2009 6:47 PM

Answer 1

sumant14 wrote:
So here I got couple of questions.
1) What if I create new instace everytime, will that cause any trouble in the memory point-of-view? i.e. load trouble?If you create just ONE object occasionally? Don't waste your time worrying about that. Unless you're doing this thousands of times each second.
2) What is the difference between 2 nd step in each scenario ? I can't get the exact difference.The first one just gets the properties file from the classpath. The second one is a bizarre hack which might do the same thing, or it might fail in certain circumstances.