public class DBHelper {		public static DataSource ds = JNDIDataSource.getDS();	public static ThreadLocal
    
      container = new ThreadLocal
     
      ();		public static ThreadLocal
      
        getContainer(){		return container;	}		public static DataSource getDataSource(){		return ds;	}		public static void startTransaction(){		Connection conn = container.get();		if(conn==null){			conn = getConnection();			container.set(conn);		}		try{			conn.setAutoCommit(false);		}catch(SQLException e){			throw new RuntimeException(e.getMessage(),e);		}	}	public static void commit(){		Connection conn = container.get();		if(conn!=null){			try{				conn.commit();			}catch (SQLException e) {				throw new RuntimeException(e.getMessage(),e);			}		}	}	public static void rollback(){		Connection conn = container.get();		if(conn!=null){			try{				conn.rollback();			}catch(SQLException e){				throw new RuntimeException(e.getMessage(),e);			}		}	}		public static void close(){		Connection conn = container.get();		if(conn!=null){			try{				conn.close();			}catch(SQLException e){							}finally{				container.remove();			}		}	}	public static Connection getConnection(){		try{			return ds.getConnection();		}catch(Exception e){			throw new RuntimeException();		}	}	public static QueryRunner getQueryRunner(){		QueryRunner qr = new QueryRunner(ds);		return qr;	}	}