fixed header value type

org.springframework.test/src/main/java/org/springframework/mock/web/HeaderValueHolder.java

@@ -16,6 +16,7 @@
 
 package org.springframework.mock.web;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedList;
@@ -58,6 +59,14 @@ class HeaderValueHolder {
 		return Collections.unmodifiableList(this.values);
 	}
 
+	public List<String> getStringValues() {
+		List<String> stringList = new ArrayList<String>(this.values.size());
+		for (Object value : this.values) {
+			stringList.add(value.toString());
+		}
+		return Collections.unmodifiableList(stringList);
+	}
+
 	public Object getValue() {
 		return (!this.values.isEmpty() ? this.values.get(0) : null);
 	}

org.springframework.test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -678,9 +678,9 @@ public class MockHttpServletRequest implements HttpServletRequest {
 		return (header != null ? header.getValue().toString() : null);
 	}
 
-	public Enumeration<Object> getHeaders(String name) {
+	public Enumeration<String> getHeaders(String name) {
 		HeaderValueHolder header = HeaderValueHolder.getByName(this.headers, name);
-		return Collections.enumeration(header != null ? header.getValues() : Collections.emptyList());
+		return Collections.enumeration(header != null ? header.getStringValues() : new LinkedList<String>());
 	}
 
 	public Enumeration<String> getHeaderNames() {

org.springframework.test/src/main/java/org/springframework/mock/web/MockHttpServletResponse.java

@@ -307,7 +307,7 @@ public class MockHttpServletResponse implements HttpServletResponse {
 	 * @param name the name of the header
 	 * @return the associated header values, or an empty List if none
 	 */
-	public List getHeaders(String name) {
+	public List<Object> getHeaders(String name) {
 		HeaderValueHolder header = HeaderValueHolder.getByName(this.headers, name);
 		return (header != null ? header.getValues() : Collections.emptyList());
 	}