ExceptionInInitializerError with logger

Question

Hello,
when I run my application I'm always getting the following error:
Exception in thread "AWT-EventQueue-0" java.lang.ExceptionInInitializerError
     at helios.visual.PreferencesGUI.<init>(PreferencesGUI.java:48)
     at helios.visual.MainGUI.actionPerformed(MainGUI.java:672)
Caused by: java.lang.NullPointerException
     at helios.properties.LogProperties.init(LogProperties.java:63)
     at helios.properties.LogProperties.<init>(LogProperties.java:33)
     at helios.properties.LogProperties.<clinit>(LogProperties.java:15)
     ... 28 more
This is a piece of the code:
public class LogProperties
     private final static LogProperties instance = new LogProperties();
     //Logger
     static Logger logger = Logger.getLogger("helios.properties.LogProperties");
     //Objects
     private DirectoriesAndFiles df = DirectoriesAndFiles.getInstance();
     private Message m = Message.getInstance();
     //Other
     private File inputfile;
     private FileInputStream inputstream;
     private FileOutputStream outputstream;
     private Properties properties = new Properties();
     //Constructor
     private LogProperties()
          init();
     //Get instance of LogProperties
     public static LogProperties getInstance()
          return instance;
     //Load the properties from the appropriate properties file
     private void init()
               try
               logger.info("Loading LogProperties.");
               inputfile = new File(df.getPropertiesPath() + df.getLogPropertiesName());
               inputstream = new FileInputStream(inputfile);
               properties.load(inputstream);
          catch (IOException e)
               m.showErrorMessage(e.getMessage());
          finally
               try
                    inputstream.close();
               catch(IOException e)
                    e.printStackTrace()
          }So as soon as my application instantiates this LogProperties class I get this error.
I don't know if the fact that this is written according to the Singleton pattern has something
to do with it.
When I set the line "logger.info("Loading LogProperties.");" in comment, then the error is not thrown.
So as soon as my logger wants to log something I'm gettting into trouble.
Does anyone know what could be the problem here. It's giving me a headache.
Thx.
Message was edited by:
Mynca

Answer 1

Yes, it's because of static, as malcolmmc suggested. What he is also saying is:
Switch the order of the following two lines:
private final static LogProperties instance = new LogProperties();
//Logger
static Logger logger = Logger.getLogger("helios.properties.LogProperties");Then logger will be initialized first, and LogProperties will be able to be constructed.
Is logger used by other classes in the package? If not, it could be private and non-static, and then you could leave the order that you had.