Objects with multi-threaded access should not lazily populate a hash field

Issue. SPR-11428
(cherry picked from commit 72fe7eb)

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -44,7 +44,7 @@ public class MethodParameter {
 
 	private final Method method;
 
-	private final Constructor constructor;
+	private final Constructor<?> constructor;
 
 	private final int parameterIndex;
 
@@ -65,8 +65,6 @@ public class MethodParameter {
 
 	Map<TypeVariable, Type> typeVariableMap;
 
-	private int hash = 0;
-
 
 	/**
 	 * Create a new MethodParameter for the given method, with nesting level 1.
@@ -100,7 +98,7 @@ public class MethodParameter {
 	 * @param constructor the Constructor to specify a parameter for
 	 * @param parameterIndex the index of the parameter
 	 */
-	public MethodParameter(Constructor constructor, int parameterIndex) {
+	public MethodParameter(Constructor<?> constructor, int parameterIndex) {
 		this(constructor, parameterIndex, 1);
 	}
 
@@ -112,7 +110,7 @@ public class MethodParameter {
 	 * (typically 1; e.g. in case of a List of Lists, 1 would indicate the
 	 * nested List, whereas 2 would indicate the element of the nested List)
 	 */
-	public MethodParameter(Constructor constructor, int parameterIndex, int nestingLevel) {
+	public MethodParameter(Constructor<?> constructor, int parameterIndex, int nestingLevel) {
 		Assert.notNull(constructor, "Constructor must not be null");
 		this.constructor = constructor;
 		this.parameterIndex = parameterIndex;
@@ -138,7 +136,6 @@ public class MethodParameter {
 		this.nestingLevel = original.nestingLevel;
 		this.typeIndexesPerLevel = original.typeIndexesPerLevel;
 		this.typeVariableMap = original.typeVariableMap;
-		this.hash = original.hash;
 	}
 
 
@@ -156,24 +153,24 @@ public class MethodParameter {
 	 * <p>Note: Either Method or Constructor is available.
 	 * @return the Constructor, or {@code null} if none
 	 */
-	public Constructor getConstructor() {
+	public Constructor<?> getConstructor() {
 		return this.constructor;
 	}
 
 	/**
 	 * Returns the wrapped member.
-	 * @return the member
+	 * @return the Method or Constructor as Member
 	 */
 	private Member getMember() {
-		return this.method != null ? this.method : this.constructor;
+		return (this.method != null ? this.method : this.constructor);
 	}
 
 	/**
 	 * Returns the wrapped annotated element.
-	 * @return the annotated element
+	 * @return the Method or Constructor as AnnotatedElement
 	 */
 	private AnnotatedElement getAnnotatedElement() {
-		return this.method != null ? this.method : this.constructor;
+		return (this.method != null ? this.method : this.constructor);
 	}
 
 	/**
@@ -241,12 +238,12 @@ public class MethodParameter {
 				Integer index = getTypeIndexForCurrentLevel();
 				Type arg = ((ParameterizedType) type).getActualTypeArguments()[index != null ? index : 0];
 				if (arg instanceof Class) {
-					return (Class) arg;
+					return (Class<?>) arg;
 				}
 				else if (arg instanceof ParameterizedType) {
 					arg = ((ParameterizedType) arg).getRawType();
 					if (arg instanceof Class) {
-						return (Class) arg;
+						return (Class<?>) arg;
 					}
 				}
 			}
@@ -423,29 +420,14 @@ public class MethodParameter {
 		}
 		if (obj != null && obj instanceof MethodParameter) {
 			MethodParameter other = (MethodParameter) obj;
-
-			if (this.parameterIndex != other.parameterIndex) {
-				return false;
-			}
-			else if (this.getMember().equals(other.getMember())) {
-				return true;
-			}
-			else {
-				return false;
-			}
+			return (this.parameterIndex == other.parameterIndex && getMember().equals(other.getMember()));
 		}
 		return false;
 	}
 
 	@Override
 	public int hashCode() {
-		int result = this.hash;
-		if (result == 0) {
-			result = getMember().hashCode();
-			result = 31 * result + this.parameterIndex;
-			this.hash = result;
-		}
-		return result;
+		return (getMember().hashCode() * 31 + this.parameterIndex);
 	}
 
 
@@ -462,7 +444,7 @@ public class MethodParameter {
 			return new MethodParameter((Method) methodOrConstructor, parameterIndex);
 		}
 		else if (methodOrConstructor instanceof Constructor) {
-			return new MethodParameter((Constructor) methodOrConstructor, parameterIndex);
+			return new MethodParameter((Constructor<?>) methodOrConstructor, parameterIndex);
 		}
 		else {
 			throw new IllegalArgumentException(