Source not found classloader.class

Question

I wrote the following code to read information from an online source:

public String ReadUrl(){ BufferedReader br = null; String result = null; try { URL url = new URL(this.url); br = new BufferedReader(new InputStreamReader(url.openStream())); String line = null; while ((line = br.readLine()) != null) result += line; } catch (IOException e) { } return result; } 

this.url as follows: "http://example.com/json.php" . When I want to open this application in a virtual machine, I get this error in Eclipse:

The source attachment does not contain a source for the classloader.class file

Where is the problem? (I updated the Eclipse and Android SDK).