ROIShape.add(ROIShape r) yields incorrect ROI. This also occurs on subtract,
intersect and other methods. Below are the affected JCK test cases:

ROIShape/Intersects_R_22
ROIShape/Intersects_R_23
ROIShape/Intersects_i4_21
ROIShape/Intersect_R_19
ROIShape/Transform_A_25
ROIShape/ROIShape_A_2
ROIShape/Add_R_3
ROIShape/ExclusiveOr_R_12
ROIShape/Subtract_R_24

The provided program at the end of this description produce the following
output on jai_1.0.1:

r1 = new ROIShape(s1) where s1 occupies the region:
 # # # -
 # # # -
 # # # -
 - - - -
r2 = new ROIShape(s2) where s2 occupies the region:
 - - - -
 - # # #
 - # # #
 - # # #
r3 = r2.add(r1) and expect the region:
 # # # -
 # # # #
 # # # #
 - # # #
r3 = r2.add(r1) got the actual region:
 - # # -
 - # # -
 - # # #
 - - # #
r3 = r2.subtract(r1) and expect the region:
 - - - -
 - - - #
 - - - #
 - # # #
r3 = r2.subtract(r1) got the actual region:
 - - - -
 - - - -
 - - - -
 - - # -
r3 = r2.intersect(r1) and expect the region:
 - - - -
 - # # -
 - # # -
 - - - -
r3 = r2.intersect(r1) got the actual region:
 - - - -
 - - # -
 - - # #
 - - - -

The program below demonstrates such behaviour:

import java.awt.Shape;
import java.awt.Rectangle;
import javax.media.jai.ROIShape;
import javax.media.jai.ROI;

public class Bug_ROIShape_Drop_Pixels {

  public static void main(String args[]) {
    ROI r3;
    String str;

    Shape s1 = new Rectangle(0, 0, 3, 3);
    ROIShape r1 = new ROIShape(s1);
    System.out.println("r1 = new ROIShape(s1) where s1 occupies the region:");
    System.out.println(" # # # -");
    System.out.println(" # # # -");
    System.out.println(" # # # -");
    System.out.println(" - - - -");

    Shape s2 = new Rectangle(1, 1, 3, 3);
    ROIShape r2 = new ROIShape(s2);
    System.out.println("r2 = new ROIShape(s2) where s2 occupies the region:");
    System.out.println(" - - - -");
    System.out.println(" - # # #");
    System.out.println(" - # # #");
    System.out.println(" - # # #");

    r3 = r2.add(r1);
    System.out.println("r3 = r2.add(r1) and expect the region:");
    System.out.println(" # # # -");
    System.out.println(" # # # #");
    System.out.println(" # # # #");
    System.out.println(" - # # #");

    System.out.println("r3 = r2.add(r1) got the actual region:");
    for(int y = 0; y < 4; y++) {
      str = "";
      for(int x = 0; x < 4; x++) {
        if(r3.contains(x, y) == true)
          str = str + " #";
        else
          str = str + " -";
      }
      System.out.println(str);
    }

    r3 = r2.subtract(r1);
    System.out.println("r3 = r2.subtract(r1) and expect the region:");
    System.out.println(" - - - -");
    System.out.println(" - - - #");
    System.out.println(" - - - #");
    System.out.println(" - # # #");

    System.out.println("r3 = r2.subtract(r1) got the actual region:");
    for(int y = 0; y < 4; y++) {
      str = "";
      for(int x = 0; x < 4; x++) {
        if(r3.contains(x, y) == true)
          str = str + " #";
        else
          str = str + " -";
      }
      System.out.println(str);
    }

    r3 = r2.intersect(r1);
    System.out.println("r3 = r2.intersect(r1) and expect the region:");
    System.out.println(" - - - -");
    System.out.println(" - # # -");
    System.out.println(" - # # -");
    System.out.println(" - - - -");

    System.out.println("r3 = r2.intersect(r1) got the actual region:");
    for(int y = 0; y < 4; y++) {
      str = "";
      for(int x = 0; x < 4; x++) {
        if(r3.contains(x, y) == true)
          str = str + " #";
        else
          str = str + " -";
      }
      System.out.println(str);
    }
  }
}