NullPointException in ResultSetHandler when java type className is null.

[fendar]

MyBatis version

3.1.1

Database vendor and version

Kylin jdbc 1.5.1

Test case or example project

@SELECT("select a,b from table limit 1")
Map<String, Object> selectOne();

Steps to reproduce

Expected result

selectOne will return a map contain result select

Actual result

Error:
NullPointException when handling resultSet, root cause is Class.forName(null)

in FastResultSetHandler.java (DefaultResultSetHandler named in later verison)
the getTypeHandler method will throw NPE when classNames.get() return null.However, mybatis will handler the situation when can not load class(from classNames.get()).So it is ok when classNames.get() return null or can not load the class, we can ignore null.And we I ignore null,mybatis work well and return the result what I expected.
(I can not upload the image, so I paste the code)
In mybatis 3.1.1 which will throw NPE

final Class javaType = resolveClass((String)classNames.get(index)); //classNames.get() will return null in kylin-jdbc 1.5.1
  if(javaType != null && jdbcType != null) {`
       handler = typeHandlerRegistry.getTypeHandler(javaType, jdbcType);
   } else if(javaType != null) {
        handler = typeHandlerRegistry.getTypeHandler(javaType);
   } else if(jdbcType != null) { //notice:mybatis will get type handler by jdbcType if javaType is null
         handler = typeHandlerRegistry.getTypeHandler(jdbcType);
  }

so if catch the NPE,maybe it will ok,and result is what I expected, following is code

final Class javaType = classNames.get(index) == null ? null : resolveClass((String)classNames.get(index));

[fendar]

I want to use plugin to handle this,but it is not easy

[harawata]

Hi,

Have you verified that the proposed change actually fixed your problem?
I just took a quick look at the driver code, but it is doubtful that MyBatis can return the column value if the column label was null.

Regards,
Iwao

[fendar]

yeah,I am sure it fixed my problem.I changed the mybatis source code and mvn install in local repo.Then I debug my program, it worked well.
The jdbcType of column is not null while javaType is.

Thanks for your replied

[harawata]

Ah, sorry, I got confused.
I'll take a look later.

[harawata]

Hi @fendar ,
It should be fixed in the latest 3.4.1-SNAPSHOT.
I would appreciate if you could test it with your solution.
Thank you for the report!

[fendar]

Great!
I will update mybatis