System server for data processing with multiple clients and a data processing method

Disclosed is a system server for data processing between the server and more than one client connected via wired or wireless communication network and a data processing method. The system server includes a connecting module for establishing connection with a client and cutting off the connection, a data transmitting module for receiving and/or sending data from or to the client, a thread managing module for creating a thread and assigning the thread to the client, a session information database for storing an identifier of a session assigned to the client connected and information on a state of data which the client requests the server to process ("data to be processed") being processed by the session, and a session managing module for monitoring the state of data processing and updating the information on the state of data processing stored in the session information database, the session managing module closing the session in case it is determined that data processing is not being performed by the session on the basis of the information on the state of data processing stored in the session information database.