test/java/lang/Character/UnicodeBlock/NonOptimalMapSize.java

rev 12008 : [mq]: XXXXXXX-Remove-INITIAL_CAPACITY-constant

@@ -40,18 +40,22 @@
         Map<?,?> map = (Map<?,?>)mapField.get(null);
         if (!map.getClass().equals(HashMap.class)) {
             throw new RuntimeException(
                     "Character.UnicodeBlock.map is expected to be HashMap");
         }
-        int mapSize = map.size();
 
-        Field sizeField = ubCls.getDeclaredField("INITIAL_CAPACITY");
-        sizeField.setAccessible(true);
-        int INITIAL_CAPACITY = sizeField.getInt(null);
+        // This is the initial size of Character.UnicodeBlock.map
+        // See src/java.base/share/classes/java/lang/Character.java
+        int initialCapacity = (int)(510 / 0.75f + 1.0f);
+
+        // We will check that the capacity was sufficient:
+        // - create a new HashMap with this initial capacity
+        // - insert map.size() elements in it
+        // - check that the internal storage wasn't reallocated
 
         // Construct a HashMap with specified initial capacity
-        HashMap<Object,Object> map1 = new HashMap<>(INITIAL_CAPACITY);
+        HashMap<Object,Object> map1 = new HashMap<>(initialCapacity);
         Class<?> hmCls = HashMap.class;
         Field tableField = hmCls.getDeclaredField("table");
         tableField.setAccessible(true);
         // ... and fill it up
         map1.put(new Object(), new Object());