How-to articles, tricks, and solutions about JDBC

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure is an exception that is thrown when there is a failure in the communication link between your Java program and the MySQL database. This can happen for a variety of reason

To connect a Java application to a MySQL database, you need to use the JDBC (Java Database Connectivity) API.

To connect to a SQL Server database using JDBC, you will need to use the JDBC driver for SQL Server.

To find out your MySQL connection details, you will need to look in your MySQL configuration files. The specific location of these files will depend on how you installed MySQL, but common locations include /etc/my.cnf,

To connect to an Oracle database using a service name instead of a SID (System Identifier), you can use the thin driver and specify the connection URL in the following format:

To get the row count using a ResultSet object in Java, you can use the last() method to move the cursor to the last row, and then use the getRow() method to get the row number:

To check if a ResultSet object contains any results in Java, you can use the next method of the ResultSet class.

A java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES) error typically indicates that the MySQL server is unable to authenticate the user with the provided username and password.

If you are using MySQL JDBC Driver version 5.1.33 and you are experiencing issues with time zones, there are a few things you can try:

A "communications link failure" error when using JDBC and MySQL can be caused by several factors. Here are a few potential solutions: