NullPointerException in ReuseExecutor.hasStatementFor() about mybatis HOT 8 CLOSED

I have the same problem. It happens when I : 
- execute an update
- commit
- execute the SAME update,

The problem is in ReuseExecutor.hasStatementFor(...) :

This method does a "statementMap.get(sql).getConnection().isClosed()", but
"statementMap.get(sql).getConnection()" returns null since doFlushStatements 
(in the
same class) was called during the last commit.
doFlushStatements invokes closeStatement() on all statements cached in 
statementMap,
and it seems this set their connection to null (maybe it depends on JdbcDrivers 
? I
use mysql-connector-java-5.1.12-bin.jar).

I suggest adding "statementMap.clear();" in doFlushStatements after having 
closed all
the statements it contains.

What do you think about this ?
Thank you.

Luc Vidal

I am unable to reproduce the error even with the 
mysql-connector-java-5.1.12-bin.jar driver. I seems that it may depends on your 
configuration. I use JNDI with JDBC transactions.

Still, adding "statementMap.clear();" in ReuseExecutor.doFlushStatements() 
makes sense so I've applied the change in mybatis trunk. Can one of you two 
checkout the code and check if it works?

To test, I did a simple (using reuseExecutor) :

openSession();
System.out.println("select 1");
selectXXX();
System.out.println("commit");
commit();
System.out.println("select 2");
selectXXX();
System.out.println("commit");
commit();

With the old version, I get : 
select 1
commit
select 2
com.sfr.bt.sh.dmc.callengine.dao.DatabaseException: 
org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.NullPointerException
### The error may exist in 
com/sfr/bt/sh/dmc/callengine/dao/engine/ImportMapper.xml
### The error may involve 
com.sfr.bt.sh.dmc.callengine.dao.engine.ImportMapper.selectImport
### The error occurred while executing a query
### Cause: java.lang.NullPointerException
        at com.sfr.bt.sh.dmc.callengine.dao.engine.EngineDao.selectImport(EngineDao.java:129)
        at com.sfr.bt.sh.dmc.callengine.Main.main(Main.java:33)
Caused by: org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.lang.NullPointerException
### The error may exist in 
com/sfr/bt/sh/dmc/callengine/dao/engine/ImportMapper.xml
### The error may involve 
com.sfr.bt.sh.dmc.callengine.dao.engine.ImportMapper.selectImport
### The error occurred while executing a query
### Cause: java.lang.NullPointerException
        at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:8)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:61)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:53)
        at org.apache.ibatis.binding.MapperMethod.executeForList(MapperMethod.java:82)
        at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
        at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:35)
        at $Proxy1.selectImport(Unknown Source)
        at com.sfr.bt.sh.dmc.callengine.dao.engine.EngineDao.selectImport(EngineDao.java:127)
        ... 1 more
Caused by: java.lang.NullPointerException
        at org.apache.ibatis.executor.ReuseExecutor.hasStatementFor(ReuseExecutor.java:68)
        at org.apache.ibatis.executor.ReuseExecutor.prepareStatement(ReuseExecutor.java:55)
        at org.apache.ibatis.executor.ReuseExecutor.doQuery(ReuseExecutor.java:38)
        at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:94)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:72)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:59)
        ... 7 more


whereas with the svn version :
select 1
commit
select 2
commit
update 1
commit
update 2
commit


So the change works.

Luc Vidal