fix(java): fix TypeRef getSubType

java/benchmark/src/test/java/org/apache/fury/benchmark/state/JsonTest.java

@@ -0,0 +1,57 @@
+/*
+ * 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.fury.benchmark.state;
+
+import com.alibaba.fastjson2.JSONObject;
+import org.apache.fury.Fury;
+import org.apache.fury.config.CompatibleMode;
+import org.apache.fury.config.Language;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class JsonTest {
+  public static class DemoResponse {
+    private JSONObject json;
+
+    public DemoResponse(JSONObject json) {
+      this.json = json;
+    }
+  }
+
+  @Test
+  public void testSerializeJson() {
+    // For issue: https://github.com/apache/incubator-fury/issues/1604
+    JSONObject jsonObject = new JSONObject();
+    jsonObject.put("k1", "v1");
+    jsonObject.put("k2", "v2");
+    DemoResponse resp = new DemoResponse(jsonObject);
+    Fury fury =
+        Fury.builder()
+            .withLanguage(Language.JAVA)
+            .requireClassRegistration(false)
+            .withRefTracking(true)
+            .registerGuavaTypes(false)
+            .withCompatibleMode(CompatibleMode.COMPATIBLE)
+            .build();
+    byte[] serialized = fury.serialize(resp);
+    DemoResponse o = (DemoResponse) fury.deserialize(serialized);
+    Assert.assertEquals(o.json, jsonObject);
+  }
+}

java/fury-core/src/main/java/org/apache/fury/reflect/TypeRef.java

@@ -498,15 +498,6 @@ private void populateTypeMappings(
       for (int i = 0; i < fromArgs.length; i++) {
         populateTypeMappings(mappings, fromArgs[i], toArgs[i]);
       }
-    } else if (supertypeWithArgsFromSubtype instanceof Class) {
-      if (toType instanceof WildcardType) {
-        return; // Okay to say Foo is <?>
-      }
-      // Can't map from a raw class to anything other than itself or a wildcard.
-      // You can't say "assuming String is Integer".
-      // And we don't support "assuming String is T"; user has to say "assuming T is String".
-      throw new IllegalArgumentException(
-          "No type mapping from " + supertypeWithArgsFromSubtype + " to " + toType);
     } else if (supertypeWithArgsFromSubtype instanceof GenericArrayType) {
       if (toType instanceof WildcardType) {
         return; // Okay to say A[] is <?>
@@ -516,7 +507,9 @@ private void populateTypeMappings(
           ((GenericArrayType) supertypeWithArgsFromSubtype).getGenericComponentType();
       populateTypeMappings(mappings, fromComponentType, componentType);
     } else {
-      throw new AssertionError("Unknown type: " + toType);
+      if (!(supertypeWithArgsFromSubtype instanceof Class)) {
+        throw new AssertionError("Unknown type: " + toType);
+      }
     }
   }
 

java/fury-core/src/test/java/org/apache/fury/reflect/TypeRefTest.java

@@ -0,0 +1,42 @@
+/*
+ * 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.fury.reflect;
+
+import static org.testng.Assert.*;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.apache.fury.type.TypeUtils;
+import org.testng.annotations.Test;
+
+public class TypeRefTest {
+  static class MapObject extends LinkedHashMap<String, Object> {}
+
+  @Test
+  public void testGetSubtype() {
+    // For issue: https://github.com/apache/incubator-fury/issues/1604
+    TypeRef<? extends Map<String, Object>> typeRef =
+        TypeUtils.mapOf(MapObject.class, String.class, Object.class);
+    assertEquals(typeRef, TypeRef.of(MapObject.class));
+    assertEquals(
+        TypeUtils.mapOf(Map.class, String.class, Object.class),
+        new TypeRef<Map<String, Object>>() {});
+  }
+}