8281183: RandomGenerator:NextDouble() default behavior partially fixe…

…d by JDK-8280950 Reviewed-by: phh Backport-of: 77b0240d44fd356711d75bc241e198f6f89ada8f
openjdk · Nov 3, 2022 · 3b40d21 · 3b40d21 · openjdk-notifier · Nov 3, 2022
1 parent 182173a
commit 3b40d21
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Showing 3 changed files with 8 additions and 5 deletions.
diff --git a/src/java.base/share/classes/java/util/SplittableRandom.java b/src/java.base/share/classes/java/util/SplittableRandom.java
@@ -547,7 +547,7 @@ public double nextDouble(double bound) {
             throw new IllegalArgumentException(BAD_BOUND);
         double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
         return (result < bound) ?  result : // correct for rounding
-            Math.nextDown(result);
+            Math.nextDown(bound);
     }
 
     /**

diff --git a/src/java.base/share/classes/java/util/concurrent/ThreadLocalRandom.java b/src/java.base/share/classes/java/util/concurrent/ThreadLocalRandom.java
@@ -414,7 +414,7 @@ public double nextDouble(double bound) {
             throw new IllegalArgumentException(BAD_BOUND);
         double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
         return (result < bound) ? result : // correct for rounding
-            Math.nextDown(result);
+            Math.nextDown(bound);
     }
 
     /**

diff --git a/test/jdk/java/util/Random/RandomNextDoubleBoundary.java b/test/jdk/java/util/Random/RandomNextDoubleBoundary.java
@@ -24,7 +24,7 @@
 /*
  * @test
  * @summary Verify nextDouble stays within range
- * @bug 8280550 8280950
+ * @bug 8280550 8280950 8281183
  */
 
 import java.util.SplittableRandom;
@@ -68,8 +68,11 @@ public static void nextDoublesWithRange(double origin, double bound) {
         SplittableRandom rg = new SplittableRandom(42L);
         double value = rg.nextDouble(origin, bound);
 
-        assertTrue(value >= origin);
-        assertTrue(value < bound);
+        if (bound > 0) {
+            value = rg.nextDouble(bound); // Equivalent to nextDouble(0.0, bound)
+            assertTrue(value >= 0.0);
+            assertTrue(value < bound);
+        }
     }
 
     public static void assertTrue(boolean condition) {