Major Description
spec says "This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort."
but Harmony's implementation is not, which cause eut failure in org.eclipse.jdt.core.tests.compiler.test074 - 1.3
see the following test:
public class TestArrays {
public static void main(String[] args) {
Element[] array = new Element[11];
array[0] = new Element(122);
array[1] = new Element(146);
array[2] = new Element(178);
array[3] = new Element(208);
array[4] = new Element(117);
array[5] = new Element(146);
array[6] = new Element(173);
array[7] = new Element(203);
array[8] = new Element(56);
array[9] = new Element(82);
array[10] = new Element(96);
for (int i = 0; i < array.length; i++)
Arrays.sort(array, new ElementComparator());
for (int i = 0; i < array.length; i++) { System.out.println("Element value is " + array[i].getValue() + " index is " + array[i].getIndex()); }
}
public static class Element {
private int value;
private int index;
public int getIndex()
{ return index; }private static int count = 0;
public int getValue()
{ return value; }public void setValue(int value)
{ this.value = value; }public Element(int value)
{ this.value = value; index = count++; }}
public static class ElementComparator implements Comparator {
public int compare(Object arg0, Object arg1)
{ return ((Element) arg0).getValue() - ((Element) arg1).getValue(); } }
}
notice array[1] and array[5] has the same value, the indexes are 1 and 5 corresponding, after a stable sort, element has index 1 should be ahead of element has index 5
output of RI:
=========before sort=============
Element value is 122 index is 0
Element value is 146 index is 1
Element value is 178 index is 2
Element value is 208 index is 3
Element value is 117 index is 4
Element value is 146 index is 5
Element value is 173 index is 6
Element value is 203 index is 7
Element value is 56 index is 8
Element value is 82 index is 9
Element value is 96 index is 10
=========after sort=============
Element value is 56 index is 8
Element value is 82 index is 9
Element value is 96 index is 10
Element value is 117 index is 4
Element value is 122 index is 0
Element value is 146 index is 1
Element value is 146 index is 5
Element value is 173 index is 6
Element value is 178 index is 2
Element value is 203 index is 7
Element value is 208 index is 3
output of Harmony:
=========before sort=============
Element value is 122 index is 0
Element value is 146 index is 1
Element value is 178 index is 2
Element value is 208 index is 3
Element value is 117 index is 4
Element value is 146 index is 5
Element value is 173 index is 6
Element value is 203 index is 7
Element value is 56 index is 8
Element value is 82 index is 9
Element value is 96 index is 10
=========after sort=============
Element value is 56 index is 8
Element value is 82 index is 9
Element value is 96 index is 10
Element value is 117 index is 4
Element value is 122 index is 0
Element value is 146 index is 5
Element value is 146 index is 1
Element value is 173 index is 6
Element value is 178 index is 2
Element value is 203 index is 7
Element value is 208 index is 3
notice that in Harmony index 1 and 5 is out of order after sort