fix(java): fix row type enum properties

java/fury-core/src/main/java/org/apache/fury/type/TypeUtils.java

@@ -681,6 +681,8 @@ private static boolean isSupported(TypeRef<?> typeRef, TypeResolutionContext ctx
       }
       Tuple2<TypeRef<?>, TypeRef<?>> mapKeyValueType = getMapKeyValueType(typeRef);
       return isSupported(mapKeyValueType.f0) && isSupported(mapKeyValueType.f1);
+    } else if (cls.isEnum()) {
+      return true;
     } else {
       ctx.checkNoCycle(typeRef);
       return isBean(typeRef, ctx.appendTypePath(typeRef));

java/fury-format/src/main/java/org/apache/fury/format/encoder/Encoders.java

@@ -131,6 +131,7 @@ public static <T> RowEncoder<T> bean(Class<T> beanClass, BinaryRowWriter writer)
    *   <li>primitive types: boolean, int, double, etc.
    *   <li>boxed types: Boolean, Integer, Double, etc.
    *   <li>String
+   *   <li>Enum (as String)
    *   <li>java.math.BigDecimal, java.math.BigInteger
    *   <li>time related: java.sql.Date, java.sql.Timestamp, java.time.LocalDate, java.time.Instant
    *   <li>Optional and friends: OptionalInt, OptionalLong, OptionalDouble

java/fury-format/src/main/java/org/apache/fury/format/row/binary/BinaryUtils.java

@@ -60,6 +60,8 @@ public static String getElemAccessMethodName(TypeRef<?> type, TypeResolutionCont
       return "getMap";
     } else if (TypeUtils.isBean(type, ctx)) {
       return "getStruct";
+    } else if (type.getRawType().isEnum()) {
+      return "getString";
     } else {
       // take unknown type as OBJECT_TYPE, return as sliced MemoryBuffer
       // slice MemoryBuffer, then deserialize in EncodeExpressionBuilder.deserializeFor
@@ -98,6 +100,8 @@ public static TypeRef<?> getElemReturnType(TypeRef<?> type, TypeResolutionContex
       return TypeRef.of(BinaryMap.class);
     } else if (TypeUtils.isBean(type, ctx)) {
       return TypeRef.of(BinaryRow.class);
+    } else if (type.getRawType().isEnum()) {
+      return TypeUtils.STRING_TYPE;
     } else {
       // take unknown type as OBJECT_TYPE, return as sliced MemoryBuffer
       // slice MemoryBuffer, then deserialize in EncodeExpressionBuilder.deserializeFor

java/fury-format/src/test/java/org/apache/fury/format/encoder/EnumTest.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.fury.format.encoder;
+
+import java.util.Optional;
+import lombok.Data;
+import org.apache.fury.format.row.binary.BinaryRow;
+import org.apache.fury.memory.MemoryBuffer;
+import org.apache.fury.memory.MemoryUtils;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class EnumTest {
+  public enum TestEnum {
+    A,
+    B
+  }
+
+  @Data
+  public static class EnumValue {
+    public TestEnum f1;
+    public Optional<TestEnum> f2;
+
+    public EnumValue() {}
+  }
+
+  @Test
+  public void testEnumPresent() {
+    EnumValue v = new EnumValue();
+    v.f1 = TestEnum.B;
+    v.f2 = Optional.of(TestEnum.A);
+    RowEncoder<EnumValue> encoder = Encoders.bean(EnumValue.class);
+    BinaryRow row = encoder.toRow(v);
+    MemoryBuffer buffer = MemoryUtils.wrap(row.toBytes());
+    row.pointTo(buffer, 0, buffer.size());
+    EnumValue deserializedV = encoder.fromRow(row);
+    Assert.assertEquals(v, deserializedV);
+  }
+
+  @Test
+  public void testEnumAbsent() {
+    EnumValue v = new EnumValue();
+    v.f1 = TestEnum.A;
+    v.f2 = Optional.empty();
+    RowEncoder<EnumValue> encoder = Encoders.bean(EnumValue.class);
+    BinaryRow row = encoder.toRow(v);
+    MemoryBuffer buffer = MemoryUtils.wrap(row.toBytes());
+    row.pointTo(buffer, 0, buffer.size());
+    EnumValue deserializedV = encoder.fromRow(row);
+    Assert.assertEquals(v, deserializedV);
+  }
+}