Question

I’m using the GWT’s Constants Interface. i have an instance class class that create a Java instance of MyConstants using the GWT.create(Class) facility, and then hold it, for the use of other.

public class LocaleMsgReader {

    private static LocaleMsgReader INSTANCE = new LocaleMsgReader();
    private static ErrorMessages errorMessages;

    private LocaleMsgReader () {

    }

    public void init (){
        errorMessages =  (ErrorMessages) GWT.create(ErrorMessages.class);
    }

    public ErrorMessages getErrorMessages() {
        return errorMessages;
    }

    public static LocaleMsgReader getInstance() {
        return INSTANCE;
    }
}

on the init method the it create the java instance, but when i calling the method getErrorMessages(), i get null.
why?

Answer 1

You’re making a singleton instance for LocalMsgReader so make errorMessages a instance variable instead of a class variable by removing static, and instantiate it in the constructor.

public class LocaleMsgReader {

    private static LocaleMsgReader INSTANCE = new LocaleMsgReader();
    private ErrorMessages errorMessages;

    private LocaleMsgReader () {
        this.errorMessages =  (ErrorMessages) GWT.create(ErrorMessages.class);
    }

    public ErrorMessages getErrorMessages() {
        return errorMessages;
    }

    public static LocaleMsgReader getInstance() {
        return INSTANCE;
    }
}