ObjectUtils.nullSafeEquals allows for JVM method inlining (through reducing its bytecode size)

Issue: SPR-14349

Author: jhoeller

spring-core/src/main/java/org/springframework/util/ObjectUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -277,14 +277,14 @@ public static Object[] toObjectArray(Object source) {
 	//---------------------------------------------------------------------
 
 	/**
-	 * Determine if the given objects are equal, returning {@code true}
-	 * if both are {@code null} or {@code false} if only one is
-	 * {@code null}.
+	 * Determine if the given objects are equal, returning {@code true} if
+	 * both are {@code null} or {@code false} if only one is {@code null}.
 	 * <p>Compares arrays with {@code Arrays.equals}, performing an equality
 	 * check based on the array elements rather than the array reference.
 	 * @param o1 first Object to compare
 	 * @param o2 second Object to compare
 	 * @return whether the given objects are equal
+	 * @see Object#equals(Object)
 	 * @see java.util.Arrays#equals
 	 */
 	public static boolean nullSafeEquals(Object o1, Object o2) {
@@ -298,33 +298,47 @@ public static boolean nullSafeEquals(Object o1, Object o2) {
 			return true;
 		}
 		if (o1.getClass().isArray() && o2.getClass().isArray()) {
-			if (o1 instanceof Object[] && o2 instanceof Object[]) {
-				return Arrays.equals((Object[]) o1, (Object[]) o2);
-			}
-			if (o1 instanceof boolean[] && o2 instanceof boolean[]) {
-				return Arrays.equals((boolean[]) o1, (boolean[]) o2);
-			}
-			if (o1 instanceof byte[] && o2 instanceof byte[]) {
-				return Arrays.equals((byte[]) o1, (byte[]) o2);
-			}
-			if (o1 instanceof char[] && o2 instanceof char[]) {
-				return Arrays.equals((char[]) o1, (char[]) o2);
-			}
-			if (o1 instanceof double[] && o2 instanceof double[]) {
-				return Arrays.equals((double[]) o1, (double[]) o2);
-			}
-			if (o1 instanceof float[] && o2 instanceof float[]) {
-				return Arrays.equals((float[]) o1, (float[]) o2);
-			}
-			if (o1 instanceof int[] && o2 instanceof int[]) {
-				return Arrays.equals((int[]) o1, (int[]) o2);
-			}
-			if (o1 instanceof long[] && o2 instanceof long[]) {
-				return Arrays.equals((long[]) o1, (long[]) o2);
-			}
-			if (o1 instanceof short[] && o2 instanceof short[]) {
-				return Arrays.equals((short[]) o1, (short[]) o2);
-			}
+			return arrayEquals(o1, o2);
+		}
+		return false;
+	}
+
+	/**
+	 * Compare the given arrays with {@code Arrays.equals}, performing an equality
+	 * check based on the array elements rather than the array reference.
+	 * @param o1 first array to compare
+	 * @param o2 second array to compare
+	 * @return whether the given objects are equal
+	 * @see #nullSafeEquals(Object, Object)
+	 * @see java.util.Arrays#equals
+	 */
+	private static boolean arrayEquals(Object o1, Object o2) {
+		if (o1 instanceof Object[] && o2 instanceof Object[]) {
+			return Arrays.equals((Object[]) o1, (Object[]) o2);
+		}
+		if (o1 instanceof boolean[] && o2 instanceof boolean[]) {
+			return Arrays.equals((boolean[]) o1, (boolean[]) o2);
+		}
+		if (o1 instanceof byte[] && o2 instanceof byte[]) {
+			return Arrays.equals((byte[]) o1, (byte[]) o2);
+		}
+		if (o1 instanceof char[] && o2 instanceof char[]) {
+			return Arrays.equals((char[]) o1, (char[]) o2);
+		}
+		if (o1 instanceof double[] && o2 instanceof double[]) {
+			return Arrays.equals((double[]) o1, (double[]) o2);
+		}
+		if (o1 instanceof float[] && o2 instanceof float[]) {
+			return Arrays.equals((float[]) o1, (float[]) o2);
+		}
+		if (o1 instanceof int[] && o2 instanceof int[]) {
+			return Arrays.equals((int[]) o1, (int[]) o2);
+		}
+		if (o1 instanceof long[] && o2 instanceof long[]) {
+			return Arrays.equals((long[]) o1, (long[]) o2);
+		}
+		if (o1 instanceof short[] && o2 instanceof short[]) {
+			return Arrays.equals((short[]) o1, (short[]) o2);
 		}
 		return false;
 	}
@@ -335,6 +349,7 @@ public static boolean nullSafeEquals(Object o1, Object o2) {
 	 * this method will delegate to any of the {@code nullSafeHashCode}
 	 * methods for arrays in this class. If the object is {@code null},
 	 * this method returns 0.
+	 * @see Object#hashCode()
 	 * @see #nullSafeHashCode(Object[])
 	 * @see #nullSafeHashCode(boolean[])
 	 * @see #nullSafeHashCode(byte[])