8366829: Add java.time.Duration constants MIN and MAX

Reviewed-by: rriggs, naoto, scolebourne

Author: pavelrappo

src/java.base/share/classes/java/time/Duration.java

@@ -138,6 +138,37 @@ public final class Duration
      * Constant for a duration of zero.
      */
     public static final Duration ZERO = new Duration(0, 0);
+    /**
+     * The minimum supported {@code Duration}, which is {@link Long#MIN_VALUE}
+     * seconds.
+     *
+     * @apiNote This constant represents the smallest possible instance of
+     * {@code Duration}. Since {@code Duration} is directed, the smallest
+     * possible duration is negative.
+     *
+     * The constant is intended to be used as a sentinel value or in tests.
+     * Care should be taken when performing arithmetic on {@code MIN} as there
+     * is a high risk that {@link ArithmeticException} or {@link DateTimeException}
+     * will be thrown.
+     *
+     * @since 26
+     */
+    public static final Duration MIN = new Duration(Long.MIN_VALUE, 0);
+    /**
+     * The maximum supported {@code Duration}, which is {@link Long#MAX_VALUE}
+     * seconds and {@code 999,999,999} nanoseconds.
+     *
+     * @apiNote This constant represents the largest possible instance of
+     * {@code Duration}.
+     *
+     * The constant is intended to be used as a sentinel value or in tests.
+     * Care should be taken when performing arithmetic on {@code MAX} as there
+     * is a high risk that {@link ArithmeticException} or {@link DateTimeException}
+     * will be thrown.
+     *
+     * @since 26
+     */
+    public static final Duration MAX = new Duration(Long.MAX_VALUE, 999_999_999);
     /**
      * Serialization version.
      */

src/java.base/share/classes/java/time/temporal/ChronoUnit.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -184,10 +184,9 @@ public enum ChronoUnit implements TemporalUnit {
      * Artificial unit that represents the concept of forever.
      * This is primarily used with {@link TemporalField} to represent unbounded fields
      * such as the year or era.
-     * The estimated duration of this unit is artificially defined as the largest duration
-     * supported by {@link Duration}.
+     * The estimated duration of this unit is artificially defined as {@link Duration#MAX}.
      */
-    FOREVER("Forever", Duration.ofSeconds(Long.MAX_VALUE, 999_999_999));
+    FOREVER("Forever", Duration.MAX);
 
     private final String name;
     private final Duration duration;

test/jdk/java/time/tck/java/time/TCKDuration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -71,6 +71,8 @@
 import static java.time.temporal.ChronoUnit.WEEKS;
 import static java.time.temporal.ChronoUnit.YEARS;
 import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNotEquals;
+import static org.testng.Assert.assertThrows;
 import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;
 
@@ -115,6 +117,44 @@ public void test_zero() {
         assertEquals(Duration.ZERO.getNano(), 0);
     }
 
+    @Test
+    public void test_min() {
+        assertEquals(Duration.MIN.getSeconds(), Long.MIN_VALUE);
+        assertEquals(Duration.MIN.getNano(), 0);
+        // no duration minimally less than MIN
+        assertThrows(ArithmeticException.class, () -> Duration.MIN.minusNanos(1));
+    }
+
+    @Test
+    public void test_max() {
+        assertEquals(Duration.MAX.getSeconds(), Long.MAX_VALUE);
+        assertEquals(Duration.MAX.getNano(), 999_999_999);
+        // no duration minimally greater than MAX
+        assertThrows(ArithmeticException.class, () -> Duration.MAX.plusNanos(1));
+    }
+
+    @Test
+    public void test_constant_properties() {
+        assertTrue(Duration.MIN.compareTo(Duration.MIN) == 0);
+        assertEquals(Duration.MIN, Duration.MIN);
+        assertTrue(Duration.ZERO.compareTo(Duration.ZERO) == 0);
+        assertEquals(Duration.ZERO, Duration.ZERO);
+        assertTrue(Duration.MAX.compareTo(Duration.MAX) == 0);
+        assertEquals(Duration.MAX, Duration.MAX);
+
+        assertTrue(Duration.MIN.compareTo(Duration.ZERO) < 0);
+        assertTrue(Duration.ZERO.compareTo(Duration.MIN) > 0);
+        assertNotEquals(Duration.ZERO, Duration.MIN);
+
+        assertTrue(Duration.ZERO.compareTo(Duration.MAX) < 0);
+        assertTrue(Duration.MAX.compareTo(Duration.ZERO) > 0);
+        assertNotEquals(Duration.ZERO, Duration.MAX);
+
+        assertTrue(Duration.MIN.compareTo(Duration.MAX) < 0);
+        assertTrue(Duration.MAX.compareTo(Duration.MIN) > 0);
+        assertNotEquals(Duration.MIN, Duration.MAX);
+    }
+
     //-----------------------------------------------------------------------
     // ofSeconds(long)
     //-----------------------------------------------------------------------