Ted,
I agree with this but just have a look in the error part. As far as the lang
spec, all the class variables are declared by default the local variables are
not. So in this case i guess it might be the following:
Class test{
ResultSet rs; //If it has been declared here it is initialized to default
value.
public void print(){
ResultSet rs; //IF it has been declared here and when u use it as
rs = getString(xxx) in ur method then u will defintely get a error as
mentioned
in the question.
}
}
Since the question was not clear i think the ResultSet is a local variable and
it was not initialized to a default value.
Thanks
Srini
Ted Neward wrote:
> Srini, unfortunately, you're absolutely incorrect on this. References are
> always set to null if not declared to be any other value; it's in the Java
> Lang Spec:
>
> Section 4.5.4 ("Initial Values of Variables") of the JLS:
>
> "4.5.4 Initial Values of Variables
> Every variable in a Java program must have a value before its value is used:
>
> Each class variable, instance variable, or array component is initialized
> with a default value when it is created (�15.8, �15.9, �20.3.6):
> For type byte, the default value is zero, that is, the value of (byte)0.
> For type short, the default value is zero, that is, the value of (short)0.
> For type int, the default value is zero, that is, 0.
> For type long, the default value is zero, that is, 0L.
> For type float, the default value is positive zero, that is, 0.0f.
> For type double, the default value is positive zero, that is, 0.0d.
> For type char, the default value is the null character, that is, '\u0000'.
> For type boolean, the default value is false.
> For all reference types (�4.3), the default value is null.
> Each method parameter (�8.4.1) is initialized to the corresponding argument
> value provided by the invoker of the method (�15.11).
> Each constructor parameter (�8.6.1) is initialized to the corresponding
> argument value provided by a class instance creation expression (�15.8) or
> explicit constructor invocation (�8.6.5).
> An exception-handler parameter (�14.18) is initialized to the thrown object
> representing the exception (�11.3, �14.16).
> A local variable (�14.3, �14.12) must be explicitly given a value before it
> is used, by either initialization (�14.3) or assignment (�15.25), in a way
> that can be verified by the compiler using the rules for definite assignment
> (�16).
> The example program:
>
> class Point {
> static int npoints;
> int x, y;
> Point root;
> }
>
> class Test {
> public static void main(String[] args) {
> System.out.println("npoints=" + Point.npoints);
> Point p = new Point();
> System.out.println("p.x=" + p.x + ", p.y=" + p.y);
> System.out.println("p.root=" + p.root);
> }
> }
> prints:
>
> npoints=0
> p.x=0, p.y=0
> p.root=null
>
> illustrating the default initialization of npoints, which occurs when the
> class Point is prepared (�12.3.2), and the
> default initialization of x, y, and root, which occurs when a new Point is
> instantiated. See �12 for a full description of all aspects of loading,
> linking, and initialization of classes and interfaces, plus a description of
> the instantiation of classes to make new class instances.
>
> Ted Neward
> Java Instructor, DevelopMentor ( http://www.develop.com )
> http://www.javageeks.com/~tneward
>
> -----Original Message-----
> From: Srini <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Date: Sunday, December 12, 1999 9:40 PM
> Subject: Re: error messages
>
> >very simple
> >
> >ur declaring rs as a local variable so it has to be initialized to any
> value
> >before ur accessing it. Instead of
> >
> >ResultSet rs;
> >
> >say
> >
> >ResultSet rs=null;
> >
> >and put ur code in a try and catch block.
> >
> >Hope this Helps
> >Srini
> >
> >Kelsey Fedde wrote:
> >
> >> JDBCServlet.java:115: Variable rs may not have been initialized.
> >> String sd = rs.getString(2);
> >> �
> >> JDBCServlet.java:115: Exception java.sql.SQLException must be caught, or
> it
> >> must
> >> be declared in the throws clause of this method.
> >> String sd = rs.getString(2);
> >>
> >> p.s. the 2 is meant to refer to line 2 of a db2 table I am accessing
> this
> >> table from OS/390
> >>
> >> I can't find and correct the error (been working on this for hours) I
> dont'
> >> have a debugger and
> >> write entirely in notepad....
> >> suggestions?
> >>
> >> thanks,
> >> Kelsey
> >>
> >>
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