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  12  * version 2 for more details (a copy is included in the LICENSE file that
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  23 
  24 /**
  25  * @test
  26  * @bug 8080535 8191410 8215194
  27  * @summary Expected size of Character.UnicodeBlock.map is not optimal
  28  * @library /test/lib
  29  * @modules java.base/java.lang:open
  30  *          java.base/java.util:open
  31  * @build jdk.test.lib.util.OptimalCapacity
  32  * @run main OptimalMapSize
  33  */
  34 
  35 import java.lang.reflect.Field;
  36 import jdk.test.lib.util.OptimalCapacity;
  37 
  38 // What will be the number of the Unicode blocks in the future.
  39 //
  40 // According to http://www.unicode.org/versions/Unicode7.0.0/ ,
  41 // in Unicode 7 there will be added 32 new blocks (96 with aliases).
  42 // According to http://www.unicode.org/versions/beta-8.0.0.html ,
  43 // in Unicode 8 there will be added 10 more blocks (30 with aliases).
  44 //
  45 // After implementing support of Unicode 9 and 10 in Java, there will
  46 // be 638 entries in Character.UnicodeBlock.map.
  47 // 
  48 // As of Unicode 11, 667 entries are expected.
  49 //
  50 // Initialization of the map and this test will have to be adjusted
  51 // accordingly then.
  52 //
  53 // Note that HashMap's implementation aligns the initial capacity to
  54 // a power of two size, so it will end up 1024 (and thus succeed) in
  55 // cases, such as 638 and 667.
  56 
  57 public class OptimalMapSize {
  58     public static void main(String[] args) throws Throwable {
  59         // The initial size of Character.UnicodeBlock.map.
  60         // See src/java.base/share/classes/java/lang/Character.java
  61         Field f = Character.UnicodeBlock.class.getDeclaredField("MAP_CAPACITY");
  62         f.setAccessible(true);
  63         int initialCapacity = f.getInt(null);
  64         assert initialCapacity == (int)(667 / 0.75f + 1.0f);
  65 
  66         OptimalCapacity.ofHashMap(Character.UnicodeBlock.class,
  67                 "map", initialCapacity);
  68     }
  69 }