NullPointerException when reading a properties file in Java

Question

I am using the following code to read a properties file:

Properties pro = new Properties();
InputStream is = Thread.currentThread().getContextClassLoader().
    getResourceAsStream("resources.properties");

pro.load(is);

And when I execute the code I'm getting the following error:

Exception in thread "main" java.lang.NullPointerException
  at java.util.Properties$LineReader.readLine(Properties.java:418)
  at java.util.Properties.load0(Properties.java:337)
  at java.util.Properties.load(Properties.java:325)
  at com.ibm.rqm.integration.RQMUrlUtility.RQMRestClient.getResource(RQMRestClient.java:66)
  at com.ibm.rqm.integration.RQMUrlUtility.RQMRestClient.main(RQMRestClient.java:50)

Why am I getting a NullPointerException? And where should I save the resources.properties file?

Answer 1

It looks like ClassLoader.getResourceAsStream(String name) returns null, which then causes Properties.load to throw NullPointerException.

Here's an excerpt from documentation:

URL getResource(String name): Finds the resource with the given name. A resource is some data (images, audio, text, etc) that can be accessed by class code in a way that is independent of the location of the code.

The name of a resource is a '/'-separated path name that identifies the resource.

Returns: A URL object for reading the resource, or null if:

• the resource could not be found, or
• the invoker doesn't have adequate privileges to get the resource.

See also

• Java Tutorials/Loading Images Using getResource
  • Has examples of where/how to put and access resources in the directory/JAR file
• SDN: Location-Independent Access to Resources