Revert "Set explicit payload members to null if the input is empty (#6111)"

This reverts commit 3ec934d.

Author: Fred1155

.changes/next-release/bugfix-AWSSDKforJavav2-e2de7f3.json

@@ -27,7 +27,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.function.Supplier;
 import software.amazon.awssdk.annotations.SdkInternalApi;
 import software.amazon.awssdk.annotations.ThreadSafe;
 import software.amazon.awssdk.core.SdkBytes;
@@ -267,11 +266,6 @@ private <T extends SdkPojo> T unmarshallFromJson(SdkPojo sdkPojo, InputStream in
         return (T) unmarshallingParser.parse(sdkPojo, inputStream);
     }
 
-    @SuppressWarnings("unchecked")
-    private <T extends SdkPojo> T unmarshallMemberFromJson(Supplier<SdkPojo> constructor, InputStream inputStream) {
-        return (T) unmarshallingParser.parseMember(constructor, inputStream);
-    }
-
     private <TypeT extends SdkPojo> TypeT unmarshallResponse(SdkPojo sdkPojo,
                                                              SdkHttpFullResponse response) throws IOException {
         JsonUnmarshallerContext context = JsonUnmarshallerContext.builder()
@@ -296,7 +290,7 @@ private <TypeT extends SdkPojo> TypeT unmarshallResponse(SdkPojo sdkPojo,
             } else if (isExplicitPayloadMember(field) && field.marshallingType() == MarshallingType.SDK_POJO) {
                 Optional<AbortableInputStream> responseContent = context.response().content();
                 if (responseContent.isPresent()) {
-                    field.set(sdkPojo, unmarshallMemberFromJson(field.constructor(), responseContent.get()));
+                    field.set(sdkPojo, unmarshallFromJson(field.constructor().get(), responseContent.get()));
                 } else {
                     field.set(sdkPojo, null);
                 }

core/protocols/aws-json-protocol/src/main/java/software/amazon/awssdk/protocols/json/internal/unmarshall/JsonProtocolUnmarshaller.java

@@ -24,7 +24,6 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.function.Supplier;
 import software.amazon.awssdk.annotations.SdkInternalApi;
 import software.amazon.awssdk.annotations.ThreadSafe;
 import software.amazon.awssdk.core.SdkBytes;
@@ -73,33 +72,6 @@ public static Builder builder() {
         return new Builder();
     }
 
-    /**
-     * Parse the provided {@link InputStream} and return the deserialized {@link SdkPojo}. Unlike
-     * {@link #parse(SdkPojo, InputStream)} this method returns null if the input stream is empty. This is used to unmarshall
-     * payload members that can be null unlike top-level response pojos.
-     */
-    public SdkPojo parseMember(Supplier<SdkPojo> constructor, InputStream content) {
-        return invokeSafely(() -> {
-            try (JsonParser parser = jsonFactory.createParser(content)
-                                                .configure(JsonParser.Feature.AUTO_CLOSE_SOURCE, false)) {
-
-                JsonUnmarshallerContext c = JsonUnmarshallerContext.builder().build();
-                JsonToken token = parser.nextToken();
-                if (token == null) {
-                    return null;
-                }
-                if (token == JsonToken.VALUE_NULL) {
-                    return null;
-                }
-                if (token != JsonToken.START_OBJECT) {
-                    throw new JsonParseException("expecting start object, got instead: " + token);
-                }
-                SdkPojo pojo = constructor.get();
-                return parseSdkPojo(c, pojo, parser);
-            }
-        });
-    }
-
     /**
      * Parse the provided {@link InputStream} and return the deserialized {@link SdkPojo}.
      */

core/protocols/aws-json-protocol/src/main/java/software/amazon/awssdk/protocols/json/internal/unmarshall/JsonUnmarshallingParser.java

@@ -19,24 +19,6 @@
       }
     }
   },
-  {
-    "description": "Operation with explicit payload structure, with emtpy output is unmarshalled as null value",
-    "given": {
-      "response": {
-        "status_code": 200,
-        "body": ""
-      }
-    },
-    "when": {
-      "action": "unmarshall",
-      "operation": "OperationWithExplicitPayloadStructure"
-    },
-    "then": {
-      "deserializedAs": {
-        "PayloadMember": null
-      }
-    }
-  },
   {
     "description": "Operation with streaming payload in output is unmarshalled correctly",
     "given": {