8240734: ModuleHashes attribute not reproducible between builds

Backport-of: f4b5488

Author: RealCLanger

src/java.base/share/classes/jdk/internal/module/ModuleHashes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 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
@@ -34,6 +34,7 @@
 import java.security.NoSuchAlgorithmException;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.TreeMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
@@ -134,7 +135,7 @@ public static byte[] computeHash(Path file, String algorithm) {
      * @return ModuleHashes that encapsulates the hashes
      */
     public static ModuleHashes generate(Map<String, Path> map, String algorithm) {
-        Map<String, byte[]> nameToHash = new HashMap<>();
+        Map<String, byte[]> nameToHash = new TreeMap<>();
         for (Map.Entry<String, Path> entry: map.entrySet()) {
             String name = entry.getKey();
             Path path = entry.getValue();

src/java.base/share/classes/jdk/internal/module/ModuleHashesBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 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
@@ -34,6 +34,7 @@
 import java.util.Collections;
 import java.util.Deque;
 import java.util.HashMap;
+import java.util.TreeMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
@@ -98,7 +99,7 @@ public Map<String, ModuleHashes> computeHashes(Set<String> roots) {
         // the modules to record the hashes - it is the first matching
         // module and has not been hashed during the traversal.
         Set<String> mods = new HashSet<>();
-        Map<String, ModuleHashes> hashes = new HashMap<>();
+        Map<String, ModuleHashes> hashes = new TreeMap<>();
         builder.build()
                .orderedNodes()
                .filter(mn -> roots.contains(mn) && !mods.contains(mn))