Why do RefCursors return result sets in reverse order?

Question

Oracle XE version 10.2.0.1 (both windows and Linux perform the same).
I'm porting code from DB2 to Oracle - our environment is mostly stored procedures returning REFCURSORS to a java layer. Many of the stored procedures return more than one REFCURSOR (please no posts on the value of packages vs procs, I understand the benefit but cannot switch at this time to packages). It took me a while to figure this out, but it appears that the cursors are returned in reverse order of their OUT param position(s). My fear is that this isn't always the case, but that the cursors could be open in some random order, in which case any conditional processing I have would need to account for that. Anyone experience this? Or can any Oracle guru explain why the cursors are open in reverse order? At this point in time, I do need to process them positionally rather than naming them -
Here's a test case:
CREATE TABLE TESTCUR(
col1 NUMBER,
col2 VARCHAR2(50)
INSERT INTO TESTCUR VALUES (1, 'value for cursor 1');
INSERT INTO TESTCUR VALUES (2, 'value for cursor 2');
INSERT INTO TESTCUR VALUES (3, 'value for cursor 3');
CREATE OR REPLACE PROCEDURE TESTREFCURSORMULTI (
  testcasenumber IN NUMBER,
  cv_1 OUT SYS_REFCURSOR,
  cv_2 OUT SYS_REFCURSOR,
  cv_3 OUT SYS_REFCURSOR
AS
BEGIN
     IF testcasenumber = 1 THEN
     OPEN cv_1 FOR
          SELECT col2
          FROM TESTCUR
          WHERE col1 = 1;
     OPEN cv_2 FOR
          SELECT * FROM DUAL WHERE 1=0;
     OPEN cv_3 FOR
          SELECT * FROM DUAL WHERE 1=0;
     ELSE
          IF testcasenumber = 2 THEN
          OPEN cv_1 FOR
               SELECT col2
               FROM TESTCUR
               WHERE col1 = 2;
          OPEN cv_2 FOR
               SELECT * FROM DUAL WHERE 1=0;
          OPEN cv_3 FOR
               SELECT * FROM DUAL WHERE 1=0;
          ELSE
               OPEN cv_1 FOR
                    SELECT col2
                    FROM TESTCUR
                    WHERE col1 = 1;
               OPEN cv_2 FOR
                    SELECT col2
                    FROM TESTCUR
                    WHERE col1 = 2;
               OPEN cv_3 FOR
                    SELECT col2
                    FROM TESTCUR
                    WHERE col1 = 3;
          END IF;
     END IF;
END;
set autoprint on
var rc1 refcursor
var rc2 refcursor
var rc3 refcursor
begin
TESTREFCURSORMULTI(
testcasenumber => 3,
cv_1 => :rc1,
cv_2 => :rc2,
cv_3 => :rc3)
end;
/     Here are the results when opening all three:
SQL> begin
  2  TESTREFCURSORMULTI(
  3  testcasenumber => 3,
  4  cv_1 => :rc1,
  5  cv_2 => :rc2,
  6  cv_3 => :rc3)
  7  ;
  8  end;
  9  /
PL/SQL procedure successfully completed.
COL2
value for cursor 3
COL2
value for cursor 2
COL2
value for cursor 1Results when opening 1:
SQL> set autoprint on
SQL> var rc1 refcursor
SQL> var rc2 refcursor
SQL> var rc3 refcursor
SQL> begin
  2  TESTREFCURSORMULTI(
  3  testcasenumber => 1,
  4  cv_1 => :rc1,
  5  cv_2 => :rc2,
  6  cv_3 => :rc3)
  7  ;
  8  end;
  9  /
PL/SQL procedure successfully completed.
no rows selected
no rows selected
COL2
value for cursor 1

Answer 1

It nothing more but the way how AUTOPRINT works:
SQL>  set autoprint on
SQL> var rc1 refcursor
SQL> var rc2 refcursor
SQL> var rc3 refcursor
SQL> begin
  2  TESTREFCURSORMULTI(
  3  testcasenumber => 3,
  4  cv_1 => :rc1,
  5  cv_2 => :rc2,
  6  cv_3 => :rc3)
  7  ;
  8  end;
  9  /
PL/SQL procedure successfully completed.
COL2
value for cursor 3
COL2
value for cursor 2
COL2
value for cursor 1
SQL> set autoprint off
SQL> begin
  2  TESTREFCURSORMULTI(
  3  testcasenumber => 3,
  4  cv_1 => :rc1,
  5  cv_2 => :rc2,
  6  cv_3 => :rc3)
  7  ;
  8  end;
  9  /
PL/SQL procedure successfully completed.
SQL> print rc1
COL2
value for cursor 1
SQL> print rc2
COL2
value for cursor 2
SQL> print rc3
COL2
value for cursor 3
SQL> As you can see, right cursor returned right result, just autoprint in case of multiple variables prints results starting last open cursor:
SQL> set autoprint on
SQL> begin
  2  open :rc1 for 'select 1 from dual';
  3  open :rc2 for 'select 2 from dual';
  4  open :rc3 for 'select 3 from dual';
  5  end;
  6  /
PL/SQL procedure successfully completed.
         3
         3
         2
         2
         1
         1
SQL> begin
  2  open :rc3 for 'select 3 from dual';
  3  open :rc2 for 'select 2 from dual';
  4  open :rc1 for 'select 1 from dual';
  5  end;
  6  /
PL/SQL procedure successfully completed.
         1
         1
         2
         2
         3
         3
SQL> SY.