Properties: NullPointException

[mickylad]

Hey guys,

I'm trying to assign a String the value of a property key-value pair but I get a NullPointerException when I try to run the code.

The method, part of the HTTPThread class, is:

187    public void statusline(String version, int codeIn) {
188        
189        String code = Integer.toString(codeIn);
190        String reason = WebServer.responsecodes.getProperty(code);
191        
192        if(reason == null) {
193            
194            code = "500";
195            reason = "Internal Server Error";
196        }
197        
198        writer.print(version + " " + code + " " + reason + "\r\n");
199    }

These properties are initiated in the WebServer class like this:

44        try {
45            
46            responsecodes = new Properties();
47            responsecodes.load(new FileInputStream("properties"+separator+"responsecodes.properties"));
48            
49        } catch(IOException e) {
50            
51            // Couldn't read response codes
52            System.out.println("Error: couldn't read response codes");
53        }

The properties are loaded correctly because I can access them inside the WebServer class.

My stack trace (tester just runs HTTPThread):

debug:
Exception in thread "main" java.lang.NullPointerException
	at server.HTTPThread.statusline(HTTPThread.java:190)
	at server.HTTPThread.run(HTTPThread.java:87)
	at server.tester.main(tester.java:20)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

[mickylad]

I also get a NullPointerException for other operations that I assumed would work fine, such as:

while((header = reader.readLine()) != null) {
...
}

Why would this be? Is it something to do with how threads handle null values?

[mickylad]

This has fixed itself, but I have no idea why. I would still appreciate it if anyone could shed some light on it for future reference.
Cheers.