What is the purpose of the isValid() method in JDBC 4.0?

a) To check if a SQL query is valid

b) To check if a connection is still valid

c) To check if a ResultSet is valid

d) To check if a transaction is valid

Answer:

b) To check if a connection is still valid

Explanation:

The isValid() method in JDBC 4.0 is used to check if a database connection is still valid and open. This method is particularly useful for verifying the health of a connection before performing database operations. It helps ensure that the connection has not been closed or invalidated due to network issues, timeouts, or other factors.

Using isValid() can prevent errors and exceptions that might occur if an invalid connection is used to execute SQL statements. By checking the connection’s validity beforehand, developers can take appropriate action, such as re-establishing the connection or handling the situation gracefully, thereby improving the reliability and stability of their applications.

The isValid() method is a simple yet powerful tool for managing database connections in JDBC. It provides a straightforward way to ensure that connections are in a usable state, reducing the likelihood of runtime errors and improving the overall robustness of the application.