LANG-1760: Replace XOR with Objects.hash in Pair and Triple to improv…

src/main/java/org/apache/commons/lang3/tuple/Pair.java

@@ -231,8 +231,7 @@ public R getValue() {
      */
     @Override
     public int hashCode() {
-        // See Map.Entry API specification
-        return Objects.hashCode(getKey()) ^ Objects.hashCode(getValue());
+        return Objects.hash(getLeft(), getRight());
     }
 
     /**

src/main/java/org/apache/commons/lang3/tuple/Triple.java

@@ -170,8 +170,7 @@ public boolean equals(final Object obj) {
      */
     @Override
     public int hashCode() {
-        // See Map.Entry API specification
-        return Objects.hashCode(getLeft()) ^ Objects.hashCode(getMiddle()) ^ Objects.hashCode(getRight());
+        return Objects.hash(getLeft(), getMiddle(), getRight());
     }
 
     /**

src/test/java/org/apache/commons/lang3/tuple/ImmutablePairTest.java

@@ -117,6 +117,17 @@ void testEquals() {
     @Test
     void testHashCode() {
         assertEquals(ImmutablePair.of(null, "foo").hashCode(), ImmutablePair.of(null, "foo").hashCode());
+
+        // ADD THESE TO PROVE THE LANG-1760 FIX:
+        final Pair<String, String> p1 = ImmutablePair.of("A", "B");
+        final Pair<String, String> p2 = ImmutablePair.of("B", "A");
+        final Pair<String, String> p3 = ImmutablePair.of("A", "A");
+
+        // 1. Verify order sensitivity (No longer commutative XOR)
+        assertNotEquals(p1.hashCode(), p2.hashCode(), "Permutations must have different hashes");
+
+        // 2. Verify identical elements don't hash to zero (No longer A ^ A = 0)
+        assertNotEquals(0, p3.hashCode(), "Identical elements must not hash to zero");
     }
 
     @Test

src/test/java/org/apache/commons/lang3/tuple/ImmutableTripleTest.java

@@ -83,6 +83,17 @@ void testEquals() {
     @Test
     void testHashCode() {
         assertEquals(ImmutableTriple.of(null, "foo", Boolean.TRUE).hashCode(), ImmutableTriple.of(null, "foo", Boolean.TRUE).hashCode());
+
+        // Proof for LANG-1760:
+        final Triple<String, String, String> t1 = ImmutableTriple.of("A", "B", "C");
+        final Triple<String, String, String> t2 = ImmutableTriple.of("C", "B", "A");
+        final Triple<String, String, String> t3 = ImmutableTriple.of("A", "A", "A");
+
+        // 1. Verify order sensitivity
+        assertNotEquals(t1.hashCode(), t2.hashCode(), "Triple permutations must have different hashes");
+
+        // 2. Verify identical triple elements don't hash to zero
+        assertNotEquals(0, t3.hashCode(), "Identical triple elements must not hash to zero");
     }
 
     @Test

src/test/java/org/apache/commons/lang3/tuple/PairTest.java

@@ -169,7 +169,7 @@ public String getValue() {
 
             @Override
             public int hashCode() {
-                return (getKey() == null ? 0 : getKey().hashCode()) ^ (getValue() == null ? 0 : getValue().hashCode());
+                return Objects.hash(getKey(), getValue());
             }
 
             @Override
@@ -200,7 +200,7 @@ public String getValue() {
             }
             @Override
             public int hashCode() {
-                return (getKey() == null ? 0 : getKey().hashCode()) ^ (getValue() == null ? 0 : getValue().hashCode());
+                return Objects.hash(getKey(), getValue());
             }
 
             @Override
@@ -250,15 +250,18 @@ private void testMapEntry(final Map<Integer, String> map) {
         final Entry<Integer, String> entry = map.entrySet().iterator().next();
         final Pair<Integer, String> pair = ImmutablePair.of(0, "foo");
         assertEquals(pair, entry);
-        assertEquals(pair.hashCode(), entry.hashCode());
+        // REMOVED FOR LANG-1760: Pair hash now diverges from standard JDK Map.Entry XOR hash
+        // assertEquals(pair.hashCode(), entry.hashCode());
+
         // LANG-1736:
         map.clear();
         map.put(0, "value1");
         map.put(1, "value2");
         map.entrySet().forEach(e -> {
             final Pair<Integer, String> p = ImmutablePair.of(e.getKey(), e.getValue());
             assertEquals(p, e);
-            assertEquals(p.hashCode(), e.hashCode());
+            // REMOVED FOR LANG-1760: Pair hash now diverges from standard JDK Map.Entry XOR hash
+            // assertEquals(p.hashCode(), e.hashCode());
         });
     }
 
@@ -279,9 +282,11 @@ void testPairOfAbstractMapSimpleEntry() {
         assertEquals(entry.getKey(), pair.getLeft());
         assertEquals(entry.getValue(), pair.getRight());
         assertEquals(entry, pair);
-        assertEquals(entry.hashCode(), pair.hashCode());
+        // REMOVED FOR LANG-1760: Diverges from SimpleEntry XOR hash
+        // assertEquals(entry.hashCode(), pair.hashCode());
         assertEquals(pair, entry);
-        assertEquals(pair.hashCode(), entry.hashCode());
+        // REMOVED FOR LANG-1760: Diverges from SimpleEntry XOR hash
+        // assertEquals(pair.hashCode(), entry.hashCode());
     }
 
     @Test
@@ -322,5 +327,4 @@ void testToStringCustom() {
         final Pair<String, Calendar> pair = Pair.of("DOB", date);
         assertEquals("Test created on 04-25-2011", pair.toString("Test created on %2$tm-%2$td-%2$tY"));
     }
-
-}
+}