use a static final empty array if list is empty

primitiveCollections/src/main/java/org/lucares/collections/IntList.java

@@ -18,6 +18,8 @@ public class IntList {
 	 */
 	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
 
+	private static final int[] EMPTY_ARRAY = {};
+
 	private int[] data;
 
 	private int index = 0;
@@ -43,7 +45,7 @@ public class IntList {
 					"initial capacity must not be negative and not larger than " + MAX_ARRAY_SIZE);
 		}
 
-		data = new int[initialCapacity];
+		data = initialCapacity > 0 ? new int[initialCapacity] : EMPTY_ARRAY;
 	}
 
 	/**
@@ -283,9 +285,13 @@ public class IntList {
 	 * Call this method to reduce the memory consumption of this list.
 	 */
 	public void trim() {
-		final int[] newData = new int[index];
-		System.arraycopy(data, 0, newData, 0, index);
-		data = newData;
+		if (index == 0) {
+			data = EMPTY_ARRAY;
+		} else {
+			final int[] newData = new int[index];
+			System.arraycopy(data, 0, newData, 0, index);
+			data = newData;
+		}
 	}
 
 	@Override