unit test reproducing the issue

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/pom.xml

@@ -585,6 +585,8 @@
                         <exclude>src/test/resources/TestValidateRecord/timestamp.json</exclude>
                         <exclude>src/test/resources/TestLookupRecord/lookup-array-input.json</exclude>
                         <exclude>src/test/resources/TestLookupRecord/lookup-array-output.json</exclude>
+                        <exclude>src/test/resources/TestValidateRecord/int-maps-schema.avsc</exclude>
+                        <exclude>src/test/resources/TestValidateRecord/int-maps-data.json</exclude>
                     </excludes>
                 </configuration>
             </plugin>

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestValidateRecord.java

@@ -18,6 +18,8 @@
 package org.apache.nifi.processors.standard;
 
 import org.apache.nifi.avro.AvroReader;
+import org.apache.nifi.avro.AvroReaderWithEmbeddedSchema;
+import org.apache.nifi.avro.AvroRecordReader;
 import org.apache.nifi.avro.AvroRecordSetWriter;
 import org.apache.nifi.csv.CSVReader;
 import org.apache.nifi.csv.CSVRecordSetWriter;
@@ -31,6 +33,7 @@ import org.apache.nifi.schema.inference.SchemaInferenceUtil;
 import org.apache.nifi.serialization.DateTimeUtils;
 import org.apache.nifi.serialization.MalformedRecordException;
 import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.record.MapRecord;
 import org.apache.nifi.serialization.record.MockRecordWriter;
 import org.apache.nifi.serialization.record.Record;
 import org.apache.nifi.serialization.record.RecordField;
@@ -45,10 +48,12 @@ import org.junit.Test;
 import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import java.util.HashMap;
 import java.util.Optional;
 
 import static org.junit.Assert.assertEquals;
@@ -547,4 +552,45 @@ public class TestValidateRecord {
         final MockFlowFile validFlowFileInferredSchema = runner.getFlowFilesForRelationship(ValidateRecord.REL_VALID).get(0);
         validFlowFileInferredSchema.assertContentEquals(new File("src/test/resources/TestValidateRecord/timestamp.json"));
     }
+
+    @Test
+    public void testValidateMaps() throws IOException, InitializationException, MalformedRecordException {
+        final String validateSchema = new String(Files.readAllBytes(Paths.get("src/test/resources/TestValidateRecord/int-maps-schema.avsc")), StandardCharsets.UTF_8);
+
+        final JsonTreeReader jsonReader = new JsonTreeReader();
+        runner.addControllerService("reader", jsonReader);
+        runner.setProperty(jsonReader, SchemaAccessUtils.SCHEMA_ACCESS_STRATEGY, "schema-text-property");
+        runner.setProperty(jsonReader, SchemaAccessUtils.SCHEMA_TEXT, validateSchema);
+        runner.enableControllerService(jsonReader);
+
+        final AvroRecordSetWriter avroWriter = new AvroRecordSetWriter();
+        runner.addControllerService("writer", avroWriter);
+        runner.enableControllerService(avroWriter);
+
+        runner.setProperty(ValidateRecord.RECORD_READER, "reader");
+        runner.setProperty(ValidateRecord.RECORD_WRITER, "writer");
+        runner.setProperty(ValidateRecord.SCHEMA_ACCESS_STRATEGY, SchemaAccessUtils.SCHEMA_TEXT_PROPERTY);
+        runner.setProperty(ValidateRecord.SCHEMA_TEXT, validateSchema);
+        runner.setProperty(ValidateRecord.INVALID_RECORD_WRITER, "writer");
+        runner.setProperty(ValidateRecord.ALLOW_EXTRA_FIELDS, "false");
+
+        runner.enqueue(Paths.get("src/test/resources/TestValidateRecord/int-maps-data.json"));
+        runner.run();
+
+        runner.assertTransferCount(ValidateRecord.REL_VALID, 1);
+        final MockFlowFile validFlowFile = runner.getFlowFilesForRelationship(ValidateRecord.REL_VALID).get(0);
+
+        byte[] source = validFlowFile.toByteArray();
+
+        try (final InputStream in = new ByteArrayInputStream(source); final AvroRecordReader reader = new AvroReaderWithEmbeddedSchema(in)) {
+            final Object[] values = reader.nextRecord().getValues();
+            assertEquals("uuid", values[0]);
+            assertEquals(2, ((HashMap<?,?>) values[1]).size());
+            final Object[] data = (Object[]) values[2];
+            assertEquals(2, ( (HashMap<?,?>) ((MapRecord) data[0]).getValue("points")).size());
+            assertEquals(2, ( (HashMap<?,?>) ((MapRecord) data[1]).getValue("points")).size());
+            assertEquals(2, ( (HashMap<?,?>) ((MapRecord) data[2]).getValue("points")).size());
+        }
+    }
+
 }

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/resources/TestValidateRecord/int-maps-data.json

@@ -0,0 +1,27 @@
+{
+  "id": "uuid",
+  "points": {
+    "1": 0,
+    "2": 0
+  },
+  "data": [
+    {
+      "points": {
+        "3": 0,
+        "4": 0
+      }
+    },
+    {
+      "points": {
+        "5": 0,
+        "6": 0
+      }
+    },
+    {
+      "points": {
+        "7": 0,
+        "8": 0
+      }
+    }
+  ]
+}

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/resources/TestValidateRecord/int-maps-schema.avsc

@@ -0,0 +1,44 @@
+{
+  "name": "statistic",
+  "type": "record",
+  "fields": [
+    {
+      "name": "id",
+      "type": "string"
+    },
+    {
+      "name": "points",
+      "type": {
+        "type": "map",
+        "values": "int"
+      }
+    },
+    {
+      "name": "data",
+      "type": {
+        "type": "array",
+        "items": {
+          "name": "data",
+          "type": "record",
+          "fields": [
+            {
+              "name": "version",
+              "type": [
+                "null",
+                "string"
+              ],
+              "default": null
+            },
+            {
+              "name": "points",
+              "type": {
+                "type": "map",
+                "values": "int"
+              }
+            }
+          ]
+        }
+      }
+    }
+  ]
+}

nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/json/AbstractJsonRowRecordReader.java

@@ -160,9 +160,9 @@ public abstract class AbstractJsonRowRecordReader implements RecordReader {
                     } catch (final Exception e) {
                         return textValue;
                     }
+                default:
+                    return textValue;
             }
-
-            return textValue;
         }
 
         if (fieldNode.isArray()) {