Critical bug fix for nulll query string parameter map in API Gateway's event.

Author: sapessi

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletRequest.java

@@ -476,7 +476,11 @@ public String[] getParameterValues(String s) {
             paramKey = paramKey.toLowerCase(Locale.getDefault());
         }
         List<String> values = new ArrayList<>();
-        values.addAll(queryStringParameters.get(paramKey));
+        List<String> queryParamValues = queryStringParameters.get(paramKey);
+        if (queryParamValues != null) {
+            values.addAll(queryParamValues);
+        }
+        //values.addAll(queryStringParameters.get(paramKey));
 
         String[] formBodyValues = getFormBodyParameterCaseInsensitive(s);
         if (formBodyValues != null) {

aws-serverless-java-container-spring/src/test/java/com/amazonaws/serverless/proxy/spring/echoapp/EchoResource.java

@@ -58,7 +58,7 @@ public MapResponseModel echoServletHeaders(HttpServletRequest context) {
     }
 
     @RequestMapping(path = "/query-string", method = RequestMethod.GET)
-    public MapResponseModel echoQueryString(HttpServletRequest request) {
+    public MapResponseModel echoQueryString(HttpServletRequest request, @RequestParam(value="nonexistent", required=false) String nonexistentParamValue) {
         MapResponseModel queryStrings = new MapResponseModel();
         for (String key : request.getParameterMap().keySet()) {
             queryStrings.addValue(key, request.getParameterMap().get(key)[0]);