support for JDK 16 record type

[bzhou]

This is to address #2195 by handling record type in Reflector.java.

The Reflector change does not require newer version of java.

The corresponding test change does require JDK 16 or later.

[coveralls]

Coverage decreased (-0.06%) to 87.224% when pulling 136595c on bzhou:master into 0ccf9ba on mybatis:master.

[harawata]

Thank you, @bzhou !

I made some changes.
Please check my commits and let me know if I missed something.

[bzhou]

Looks good, thank you @harawata.

In terms of testing, in my test code, there was one case where I used
@Arg(column="property_id", javaType=PropId.class, typeHandler=PropIdTypeHandler.class),
The PropId is also a record class with just one Integer component. This is a case where the old code gets very confused and error out.

I tried run your latest simplified testing against the old Reflector code, turns out

• testSelectRecord passes
• testInsertRecord passes
• testSelectRecordAutomapping caught IllegalAccessException: Can not set final int field org.apache.ibatis.submitted.record_type.Property.id to java.lang.Integer

So I guess that's also good.

I'm good with your changes, please merge into mybatis:mybatis-3 when convenient. Thanks!

[harawata]

Thank you, @bzhou !

Based on your feedback, I have added a few more commits.

• Modified the test a little bit and now the testInsertRecord will fail with the old implementation. The difference is that the old implementation reads the field value directly while the new implementation invokes the accessor method.
• Added a new test that involving nested records. It uses nested result map which may be more flexible compared to type handler. This mapping should work with the old implementation as well.

[bzhou]

Really cool, thanks @harawata!

[harawata]

The change is merged and is in the latest 3.5.10-SNAPSHOT.
I'll comment on #2195 later.
Thanks again, @bzhou !