Fix for Jackson marshalling 4-byte characters

components/camel-jackson/src/main/java/org/apache/camel/component/jackson/AbstractJacksonDataFormat.java

@@ -19,6 +19,7 @@
 import java.io.File;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
 import java.io.Reader;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -157,7 +158,9 @@ public void marshal(Exchange exchange, Object graph, OutputStream stream) throws
         if (this.schemaResolver != null) {
             schema = this.schemaResolver.resolve(exchange);
         }
-        this.objectMapper.writerWithView(jsonView).with(schema).writeValue(stream, graph);
+        // using OutputStreamWriter because of Jackson not handling 4-byte characters properly with only a stream
+        // https://github.com/FasterXML/jackson-core/issues/223
+        this.objectMapper.writerWithView(jsonView).with(schema).writeValue(new OutputStreamWriter(stream), graph);
 
         if (contentTypeHeader) {
             exchange.getMessage().setHeader(Exchange.CONTENT_TYPE, getDefaultContentType());

components/camel-jackson/src/test/java/org/apache/camel/component/jackson/JacksonMarshalMultibyteCharactersTest.java

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.component.jackson;
+
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.component.mock.MockEndpoint;
+import org.apache.camel.test.junit5.CamelTestSupport;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+public class JacksonMarshalMultibyteCharactersTest extends CamelTestSupport {
+
+    @Test
+    public void testMarshalAndUnmarshalMap() throws Exception {
+        Map<String, Object> in = new HashMap<>();
+        // name: システム𩸽
+        in.put("name", "システム\uD867\uDE3D");
+
+        MockEndpoint mock = getMockEndpoint("mock:reverse");
+        mock.expectedMessageCount(1);
+        mock.message(0).body().isInstanceOf(Map.class);
+        mock.message(0).body().isEqualTo(in);
+
+        Object marshalled = template.requestBody("direct:in", in);
+        String marshalledAsString = context.getTypeConverter().convertTo(String.class, marshalled);
+
+        assertEquals("{\"name\":\"システム𩸽\"}", marshalledAsString);
+
+        // prior to fixing CAMEL-21199, this was the result returned by Jackson
+        assertNotEquals("{\"name\":\"システム\\uD867\\uDE3D\"}", marshalledAsString);
+
+        template.sendBody("direct:back", marshalled);
+
+        mock.assertIsSatisfied();
+    }
+
+    @Override
+    protected RouteBuilder createRouteBuilder() {
+        return new RouteBuilder() {
+
+            @Override
+            public void configure() {
+                JacksonDataFormat format = new JacksonDataFormat();
+                from("direct:in").marshal(format);
+                from("direct:back").unmarshal(format).to("mock:reverse");
+            }
+        };
+    }
+
+}