Simplify initialization of collections

Author: Steve Peters

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/model/ContainerConfig.java

@@ -4,6 +4,7 @@
 import com.amazonaws.serverless.proxy.internal.servlet.AwsProxyHttpServletRequest;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
 
@@ -237,9 +238,7 @@ public void setQueryStringCaseSensitive(boolean queryStringCaseSensitive) {
      */
     public void addBinaryContentTypes(String... contentTypes) {
         if(contentTypes != null) {
-            for(String type: contentTypes) {
-                binaryContentTypes.add(type);
-            }
+            binaryContentTypes.addAll(Arrays.asList(contentTypes));
         }
     }
 

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/model/MultiValuedTreeMap.java

@@ -168,8 +168,7 @@ public MultiValuedTreeMap<Key, Value> clone() {
         MultiValuedTreeMap<Key, Value> clone = new MultiValuedTreeMap<>();
         for (Key key : keySet()) {
             List<Value> value = get(key);
-            List<Value> newValue = new ArrayList<>();
-            newValue.addAll(value);
+            List<Value> newValue = new ArrayList<>(value);
             clone.put(key, newValue);
         }
         return clone;