SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@739488d7] was not registered for synchronization because synchronization is not active

Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@739488d7]

2019-12-14 11:29:18.044 ERROR 7620 --- [nio-8001-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null

    at org.apache.ibatis.session.defaults.DefaultSqlSession.close(DefaultSqlSession.java:263)

    at org.mybatis.spring.SqlSessionUtils.closeSqlSession(SqlSessionUtils.java:195)

    at com.baomidou.mybatisplus.extension.toolkit.SqlRunner.closeSqlSession(SqlRunner.java:234)

    at com.baomidou.mybatisplus.extension.toolkit.SqlRunner.selectList(SqlRunner.java:156)

public Object plugin(Object target) {

        logger.info("=========== plugin ================");

        return Plugin.wrap(target, this);

    }