Simplify map initial sizing

Author: idegtiarenko

server/src/main/java/org/elasticsearch/common/util/Maps.java

@@ -280,7 +280,7 @@ public static <K, V> Map<K, V> newMapWithExpectedSize(int expectedSize) {
      * @return a new pre-sized {@link HashMap}
      */
     public static <K, V> Map<K, V> newHashMapWithExpectedSize(int expectedSize) {
-        return new HashMap<>(capacity(expectedSize));
+        return HashMap.newHashMap(expectedSize);
     }
 
     /**
@@ -292,7 +292,7 @@ public static <K, V> Map<K, V> newHashMapWithExpectedSize(int expectedSize) {
      * @return a new pre-sized {@link HashMap}
      */
     public static <K, V> Map<K, V> newConcurrentHashMapWithExpectedSize(int expectedSize) {
-        return new ConcurrentHashMap<>(capacity(expectedSize));
+        return new ConcurrentHashMap<>(expectedSize);
     }
 
     /**
@@ -304,12 +304,7 @@ public static <K, V> Map<K, V> newConcurrentHashMapWithExpectedSize(int expected
      * @return a new pre-sized {@link LinkedHashMap}
      */
     public static <K, V> LinkedHashMap<K, V> newLinkedHashMapWithExpectedSize(int expectedSize) {
-        return new LinkedHashMap<>(capacity(expectedSize));
-    }
-
-    static int capacity(int expectedSize) {
-        assert expectedSize >= 0;
-        return expectedSize < 2 ? expectedSize + 1 : (int) (expectedSize / 0.75 + 1.0);
+        return LinkedHashMap.newLinkedHashMap(expectedSize);
     }
 
     /**

server/src/test/java/org/elasticsearch/common/util/MapsTests.java

@@ -32,7 +32,6 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.hasItem;
-import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
 public class MapsTests extends ESTestCase {
 
@@ -270,22 +269,6 @@ public void testFlatten() {
         }
     }
 
-    public void testCapacityIsEnoughForMapToNotBeResized() {
-        for (int i = 0; i < 1000; i++) {
-            int size = randomIntBetween(0, 1_000_000);
-            int capacity = Maps.capacity(size);
-            assertThat(size, lessThanOrEqualTo((int) (capacity * 0.75f)));
-        }
-    }
-
-    public void testCapacityForMaxSize() {
-        assertEquals(Integer.MAX_VALUE, Maps.capacity(Integer.MAX_VALUE));
-    }
-
-    public void testCapacityForZeroSize() {
-        assertEquals(1, Maps.capacity(0));
-    }
-
     @SuppressWarnings("unchecked")
     private static Object deepGet(String path, Object obj) {
         Object cur = obj;