Java 17下GSON序列化java.sql.Timestamp私有字段访问失败求助

问题背景 #

近期升级Java后，序列化从SAP Sybase数据库读取、映射为java.sql.Timestamp类型的对象时失败，通过简单的Select getdate()查询即可复现该问题。

环境配置 #

• Java 17.0.4.1（Eclipse Adoptium）
• Mac OS X 14.0

排查情况 #

• 无法添加add-opens=java.sql=ALL-UNNAMED这类JVM配置
• 调试Gson库的TypeAdapterRuntimeTypeWrapper后发现，java.sql.Timestamp对象使用的是反射适配器，因Java模块封装限制，无法访问java.sql.Timestamp#nanos私有字段导致报错

当前临时降级方案 #

采用Jackson库可正常序列化该对象，代码示例：

try {
    json = GSON.toJson(object);
} catch (Exception e) {
    log.warn("Failed to serialize JSON. Trying alternative serializer (1).", e);
    try {
        json = new ObjectMapper().writeValueAsString(object);
    } catch (Exception e1) {
        log.warn("Failed to serialize JSON. Leaving null.", e);
    }
}

报错堆栈信息 #

com.google.gson.JsonIOException: Failed making field 'java.sql.Timestamp#nanos' accessible; either increase its visibility or write a custom TypeAdapter for its declaring type.
    at com.google.gson.internal.reflect.ReflectionHelper.makeAccessible(ReflectionHelper.java:38)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:286)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:130)
    at com.google.gson.Gson.getAdapter(Gson.java:556)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:55)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:207)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:144)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:70)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:97)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:61)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:70)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:207)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:144)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:70)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:97)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:61)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:70)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:207)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:144)
    at com.google.gson.Gson.toJson(Gson.java:842)
    at com.google.gson.Gson.toJson(Gson.java:812)
    at com.google.gson.Gson.toJson(Gson.java:759)
    at com.google.gson.Gson.toJson(Gson.java:736)

Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make field private int java.sql.Timestamp.nanos accessible: module java.sql does not "opens java.sql" to unnamed module @2554782d
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(Unknown Source)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(Unknown Source)
    at java.base/java.lang.reflect.Field.checkCanSetAccessible(Unknown Source)
    at java.base/java.lang.reflect.Field.setAccessible(Unknown Source)
    at com.google.gson.internal.reflect.ReflectionHelper.makeAccessible(ReflectionHelper.java:35)

求助 #

恳请提供可行的解决思路。

内容的提问来源于stack exchange，提问作者Felix