--- jsr166/src/test/tck/ThreadLocalRandomTest.java	2016/12/10 12:39:15	1.24
+++ jsr166/src/test/tck/ThreadLocalRandomTest.java	2017/10/13 02:34:59	1.27
@@ -57,6 +57,9 @@ public class ThreadLocalRandomTest exten
      * possible values.
      */
     public void testNext() throws ReflectiveOperationException {
+        // Inhibit "An illegal reflective access operation has occurred"
+        if (!testImplementationDetails) return;
+
         ThreadLocalRandom rnd = ThreadLocalRandom.current();
         final java.lang.reflect.Method m;
         try {
@@ -382,4 +385,38 @@ public class ThreadLocalRandomTest exten
         fail("all threads generate the same pseudo-random sequence");
     }
 
+    /**
+     * Repeated calls to nextBytes produce at least values of different signs for every byte
+     */
+    public void testNextBytes() {
+        ThreadLocalRandom rnd = ThreadLocalRandom.current();
+        int n = rnd.nextInt(1, 20);
+        byte[] bytes = new byte[n];
+        outer:
+        for (int i = 0; i < n; i++) {
+            for (int tries = NCALLS; tries-->0; ) {
+                byte before = bytes[i];
+                rnd.nextBytes(bytes);
+                byte after = bytes[i];
+                if (after * before < 0)
+                    continue outer;
+            }
+            fail("not enough variation in random bytes");
+        }
+    }
+
+    /**
+     * Filling an empty array with random bytes succeeds without effect.
+     */
+    public void testNextBytes_emptyArray() {
+        ThreadLocalRandom.current().nextBytes(new byte[0]);
+    }
+
+    public void testNextBytes_nullArray() {
+        try {
+            ThreadLocalRandom.current().nextBytes(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
 }