8242312: use reproducible random in hotspot gc tests

Reviewed-by: kbarrett, tschatzl

Author: iignatev

test/hotspot/jtreg/gc/TestSoftReferencesBehaviorOnOOME.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2020, 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
@@ -25,7 +25,7 @@
 
 /**
  * @test TestSoftReferencesBehaviorOnOOME
- * @key gc
+ * @key gc randomness
  * @summary Tests that all SoftReferences has been cleared at time of OOM.
  * @requires vm.gc != "Z"
  * @library /test/lib

test/hotspot/jtreg/gc/epsilon/TestByteArrays.java

@@ -25,9 +25,10 @@
 
 /**
  * @test TestByteArrays
- * @key gc
+ * @key gc randomness
  * @requires vm.gc.Epsilon & !vm.graal.enabled
  * @summary Epsilon is able to allocate arrays, and does not corrupt their state
+ * @library /test/lib
  *
  * @run main/othervm -Xmx1g                                        -XX:+UseTLAB -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC gc.epsilon.TestByteArrays
  * @run main/othervm -Xmx1g -Xint                                  -XX:+UseTLAB -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC gc.epsilon.TestByteArrays
@@ -43,16 +44,15 @@
  */
 
 import java.util.Random;
+import jdk.test.lib.Utils;
 
 public class TestByteArrays {
-
-  static long SEED = Long.getLong("seed", System.nanoTime());
   static int COUNT = Integer.getInteger("count", 3000); // ~500 MB allocation
 
   static byte[][] arr;
 
   public static void main(String[] args) throws Exception {
-    Random r = new Random(SEED);
+    Random r = Utils.getRandomInstance();
 
     arr = new byte[COUNT * 100][];
     for (int c = 0; c < COUNT; c++) {
@@ -62,7 +62,7 @@ public static void main(String[] args) throws Exception {
       }
     }
 
-    r = new Random(SEED);
+    r = new Random(Utils.SEED);
     for (int c = 0; c < COUNT; c++) {
       byte[] b = arr[c];
       if (b.length != (c * 100)) {