Provided a Unit test that shows how the same json path statement provides a Map of objects when using Jackson configuration, but failes when Gson configuration is used.

json-path/src/test/java/com/jayway/jsonpath/BaseTest.java

@@ -118,6 +118,67 @@ public class BaseTest {
             "   \"@id\" : \"ID\"\n" +
             "}";
 
+    public static final String JSON_AWS_LAMBDA_CONTEXT = "{\n" +
+            "  \"body\": \"{\\\"test\\\":\\\"body\\\"}\",\n" +
+            "  \"resource\": \"/{proxy+}\",\n" +
+            "  \"requestContext\": {\n" +
+            "    \"resourceId\": \"123456\",\n" +
+            "    \"apiId\": \"1234567890\",\n" +
+            "    \"resourcePath\": \"/{proxy+}\",\n" +
+            "    \"httpMethod\": \"POST\",\n" +
+            "    \"requestId\": \"c6af9ac6-7b61-11e6-9a41-93e8deadbeef\",\n" +
+            "    \"accountId\": \"123456789012\",\n" +
+            "    \"identity\": {\n" +
+            "      \"apiKey\": null,\n" +
+            "      \"userArn\": null,\n" +
+            "      \"cognitoAuthenticationType\": null,\n" +
+            "      \"caller\": null,\n" +
+            "      \"userAgent\": \"Custom User Agent String\",\n" +
+            "      \"user\": null,\n" +
+            "      \"cognitoIdentityPoolId\": null,\n" +
+            "      \"cognitoIdentityId\": null,\n" +
+            "      \"cognitoAuthenticationProvider\": null,\n" +
+            "      \"sourceIp\": \"127.0.0.1\",\n" +
+            "      \"accountId\": null\n" +
+            "    },\n" +
+            "    \"stage\": \"prod\"\n" +
+            "  },\n" +
+            "  \"queryStringParameters\": {\n" +
+            "    \"lat\": 50.0,\n" +
+            "    \"lon\": 60.0,\n" +
+            "    \"timeZone\": 1\n" +
+            "  },\n" +
+            "  \"headers\": {\n" +
+            "    \"Via\": \"1.1 08f323deadbeefa7af34d5feb414ce27.cloudfront.net (CloudFront)\",\n" +
+            "    \"Accept-Language\": \"en-US,en;q=0.8\",\n" +
+            "    \"CloudFront-Is-Desktop-Viewer\": \"true\",\n" +
+            "    \"CloudFront-Is-SmartTV-Viewer\": \"false\",\n" +
+            "    \"CloudFront-Is-Mobile-Viewer\": \"false\",\n" +
+            "    \"X-Forwarded-For\": \"127.0.0.1, 127.0.0.2\",\n" +
+            "    \"CloudFront-Viewer-Country\": \"US\",\n" +
+            "    \"Accept\": \"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\",\n" +
+            "    \"Upgrade-Insecure-Requests\": \"1\",\n" +
+            "    \"X-Forwarded-Port\": \"443\",\n" +
+            "    \"Host\": \"1234567890.execute-api.us-east-1.amazonaws.com\",\n" +
+            "    \"X-Forwarded-Proto\": \"https\",\n" +
+            "    \"X-Amz-Cf-Id\": \"cDehVQoZnx43VYQb9j2-nvCh-9z396Uhbp027Y2JvkCPNLmGJHqlaA==\",\n" +
+            "    \"CloudFront-Is-Tablet-Viewer\": \"false\",\n" +
+            "    \"Cache-Control\": \"max-age=0\",\n" +
+            "    \"User-Agent\": \"Custom User Agent String\",\n" +
+            "    \"CloudFront-Forwarded-Proto\": \"https\",\n" +
+            "    \"Accept-Encoding\": \"gzip, deflate, sdch\"\n" +
+            "  },\n" +
+            "  \"pathParameters\": {\n" +
+            "    \"proxy\": \"path/to/resource\"\n" +
+            "  },\n" +
+            "  \"httpMethod\": \"POST\",\n" +
+            "  \"stageVariables\": {\n" +
+            "    \"baz\": \"qux\"\n" +
+            "  },\n" +
+            "  \"path\": \"/path/to/resource\"\n" +
+            "}";
+
+
     public Predicate.PredicateContext createPredicateContext(final Object check) {
 
         return new PredicateContextImpl(check, check, Configuration.defaultConfiguration(), new HashMap<Path, Object>());

json-path/src/test/java/com/jayway/jsonpath/GsonJsonProviderTest.java

@@ -8,6 +8,7 @@ import org.junit.Test;
 
 import java.io.IOException;
 import java.util.List;
+import java.util.Map;
 
 import static com.jayway.jsonpath.JsonPath.using;
 import static org.assertj.core.api.Assertions.assertThat;
@@ -79,6 +80,17 @@ public class GsonJsonProviderTest extends BaseTest {
         assertThat(using(GSON_CONFIGURATION).parse("{\"val\": 1}").read("val", Double.class)).isEqualTo(1D);
     }
 
+
+    @Test(expected = ClassCastException.class)
+    public void jackson_can_what_gson_cannot() {
+        final Map<String, Object> jacksonMap = using(JACKSON_CONFIGURATION).parse(JSON_AWS_LAMBDA_CONTEXT).read("$.queryStringParameters");
+        assertThat(jacksonMap.get("lat")).isEqualTo(50D);
+
+        // thorws class ClassCastException
+        final Map<String, Object> gsonMap = using(GSON_CONFIGURATION).parse(JSON_AWS_LAMBDA_CONTEXT).read("$.queryStringParameters");
+        assertThat(gsonMap.get("lat")).isEqualTo(50D);
+    }
+
     @Test
     public void list_of_numbers() {
         JsonArray objs = using(GSON_CONFIGURATION).parse(JSON_DOCUMENT).read("$.store.book[*].display-price");
@@ -107,7 +119,8 @@ public class GsonJsonProviderTest extends BaseTest {
 
     @Test
     public void test_type_ref() throws IOException {
-        TypeRef<List<FooBarBaz<Gen>>> typeRef = new TypeRef<List<FooBarBaz<Gen>>>() {};
+        TypeRef<List<FooBarBaz<Gen>>> typeRef = new TypeRef<List<FooBarBaz<Gen>>>() {
+        };
 
         List<FooBarBaz<Gen>> list = JsonPath.using(GSON_CONFIGURATION).parse(JSON).read("$", typeRef);
 
@@ -116,7 +129,8 @@ public class GsonJsonProviderTest extends BaseTest {
 
     @Test(expected = MappingException.class)
     public void test_type_ref_fail() throws IOException {
-        TypeRef<List<FooBarBaz<Integer>>> typeRef = new TypeRef<List<FooBarBaz<Integer>>>() {};
+        TypeRef<List<FooBarBaz<Integer>>> typeRef = new TypeRef<List<FooBarBaz<Integer>>>() {
+        };
 
         using(GSON_CONFIGURATION).parse(JSON).read("$", typeRef);
     }
@@ -140,6 +154,4 @@ public class GsonJsonProviderTest extends BaseTest {
     }
 
 
-
-
 }