MySQL Connection Failure: How to Fix 'Could not create connection to database server' Exception?

MySQL Connection Failure: Troubleshooting "Could not create connection to database server" Exception

This error message, "com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server," commonly occurs when attempting to establish a JDBC connection to a MySQL database. Here's how to address this issue:

Cause and Resolution:

The error typically stems from compatibility issues between older versions of MySQL Connector/J and MySQL version 8.0 or higher. To resolve this issue, upgrade to either MySQL Connector/J version 5.1.46 or, preferably, version 8.0.11 or higher.

Additional Tips:

• Ensure that MySQL Server is running and accessible from your Java application.
• Verify that the MySQL username and password provided in your connection string are correct.
• Check the MySQL Server log file (usually located at /var/log/mysql/error.log or a similar path) for any additional error messages.
• If you are using MySQL Workbench, try connecting to the database manually to rule out connectivity issues at the server level.
• Consider enabling debug logging in your Java code to obtain more detailed error information. This can be done by adding the following line to your code before the connection attempt:

java.util.logging.Logger.getLogger("com.mysql.jdbc").setLevel(Level.FINEST);

Updated Error Stack Trace:

The provided error stack trace reveals a NullPointerException within the MySQL JDBC driver, indicating a possible compatibility issue with MySQL 8.0. Upgrading MySQL Connector/J as suggested above should resolve this issue.

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