CODEWITHSUNDEEP
javajakarta-ee
Attilah
Attilah

Reputation: 17930

java configuration file

I have a method : 

private String getProperty(String property) throws IOException,ConfigException {

    // first test if the config file exists.
    String propertyFile = "DataTransfer/Config/DataTransfer.properties";

    if(!new File(propertyFile).exists()) {
        throw new ConfigException("the config file doesn't exist." +
            " Make sure the file : \""+propertyFile+"\" exists.");
    }   

    // retrieve the property
    Properties configFile = new Properties();

    configFile.load(this.getClass().getClassLoader()
        .getResourceAsStream(propertyFile));

    String prop = configFile.getProperty(property);
    return prop;
}

Unfortunately, I keep getting a java.lang.NullPointerException at the ConfigFile.load() level.

I checked my variables in debug mode, none of them is null.

I don't know what's the cause for this exception.

Upvotes: 0

Views: 4249

Answers (6)

Jan Jungnickel
Jan Jungnickel

Reputation: 2114

ClassLoader#getResourceAsStream(String) returns null if the resource cannot be found by the ClassLoader hierarchy. This will most likely be the root cause.

Classloading, especially in J2EE-Environments, is often misunterstood.

Upvotes: 1

aholub7x
aholub7x

Reputation: 818

Use

configFile.load(new FileReader(new File(propertyFile)));

to check and load in same style

Upvotes: 0

Kennet
Kennet

Reputation: 5796

Make sure that the configfile is in that particular folder and that you're actually looking in the right path. I usually add something like this before the load method:

System.out.println(this.getClass().getClassLoader().getResource(".").getFile());

This will print the absloute path

Upvotes: 0

valli
valli

Reputation: 5931

You can try like this FileInputStream infile = new FileInputStream(new File(libjavaFolder+"log4j.properties")); if(infile != null) { Properties logProps = new Properties(); logProps.load(infile); infile.close(); }

Upvotes: 0

kgiannakakis
kgiannakakis

Reputation: 104178

I refer you to this question regarding best practices for reading configuration files in J2EE environments.

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1500535

You've checked that it exists as a file in the current working directory. You haven't checked that it exists on the classpath.

If you know it exists as a file, why not load it as a file?

If you want to load it from the classpath, why not change the check to make sure it exists on the classpath?

Basically you need to be consistent between your checking and your loading.

Upvotes: 5

Related Questions