Closing the Database Connection - con.close()

This section describes how to close database connections.

When you obtained a connection object with DriverManager.getConnection() successfully, you can create statement objects and execute them with this connection object. But when you are done with this connection, you should close it to free resources associated this connection on the SQL server. To close a connection, you should call the close() method on this connection object.

The tutorial program below shows you how to call close() on a connection object. isClosed() method is called to verify the status of the connection object.

/* CloseConnection.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.sql.*;
public class CloseConnection {
  public static void main(String [] args) {
    Connection con = null;
    try {

// Obtaining a connection to SQL Server
      con = DriverManager.getConnection(
          "jdbc:sqlserver://localhost\\SQLEXPRESS;"
        + "user=herong;password=T0pSecret");

// Connection is ready to use
      DatabaseMetaData meta = con.getMetaData();
      System.out.println("Server name: "
        + meta.getDatabaseProductName());
      System.out.println("Server version: "
        + meta.getDatabaseProductVersion());

// Closing the connection
      con.close();
      if (con.isClosed())
        System.out.println("Connection closed.");

    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

If you run this program, you will get:

herong> java -cp .;mssql-jdbc-9.4.1.jre16.jar CloseConnection.java

Server name: Microsoft SQL Server
Server version: 15.00.2000
Connection closed.

Table of Contents

 About This Book

 JDBC (Java Database Connectivity) Introduction

 JDK (Java SE) Installation

 Installing and Running Java DB - Derby

 Derby (Java DB) JDBC Driver

 Derby (Java DB) JDBC DataSource Objects

 Java DB (Derby) - DML Statements

 Java DB (Derby) - ResultSet Objects of Queries

 Java DB (Derby) - PreparedStatement

 MySQL Installation on Windows

 MySQL JDBC Driver (MySQL Connector/J)

 MySQL - PreparedStatement

 MySQL - Reference Implementation of JdbcRowSet

 MySQL - JBDC CallableStatement

 MySQL CLOB (Character Large Object) - TEXT

 MySQL BLOB (Binary Large Object) - BLOB

 Oracle Express Edition Installation on Windows

 Oracle JDBC Drivers

 Oracle - Reference Implementation of JdbcRowSet

 Oracle - PreparedStatement

 Oracle - JBDC CallableStatement

 Oracle CLOB (Character Large Object) - TEXT

 Oracle BLOB (Binary Large Object) - BLOB

 Microsoft SQL Server Express Edition

Microsoft JDBC Driver for SQL Server

 Installing Microsoft JDBC Driver for SQL Server

 Loading Driver Class Automatically

 Loading Driver Class with Class.forName()

 DriverManager.getConnection() and Connection URL

 Enable TCP/IP with SQL Server Configuration Manager

 Specifying Port Number in Connection URL

 Instance Name Better than Port Number

 Specifying Instance Name in Connection URL

Closing the Database Connection - con.close()

 Specifying Database Name in Connection URL

 Incorrect Database Name in Connection URL

 Creating Connections with DataSource Class

 Microsoft JDBC Driver - Query Statements and Result Sets

 Microsoft JDBC Driver - DatabaseMetaData Object

 Microsoft JDBC Driver - DDL Statements

 Microsoft JDBC Driver - DML Statements

 SQL Server - PreparedStatement

 SQL Server CLOB (Character Large Object) - TEXT

 SQL Server BLOB (Binary Large Object) - BLOB

 JDBC-ODBC Bridge Driver - sun.jdbc.odbc.JdbcOdbcDriver

 JDBC-ODBC Bridge Driver - Flat Text Files

 JDBC-ODBC Bridge Driver - MS Access

 JDBC-ODBC Bridge Driver - MS SQL Server

 Summary of JDBC Drivers and Database Servers

 Using Connection Pool with JDBC

 Archived Tutorials

 References

 Full Version in PDF/EPUB