In Java, you can use JDBC transactions to group together a set of database operations into a single unit of work that either succeeds or fails as a whole. JDBC transactions help ensure the consistency and reliability of the data in your database.

Here are the steps to use JDBC transactions in your Java code:

1. Import the necessary JDBC classes in your Java code:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

2. Create a connection to your database using the DriverManager class:

String url = "jdbc:mysql://localhost/mydatabase";
String user = "myuser";
String password = "mypassword";
Connection connection = DriverManager.getConnection(url, user, password);

Replace "jdbc:mysql://localhost/mydatabase" with the URL to your database, and "myuser" and "mypassword" with your database credentials.

3. Set the auto-commit mode of the connection to false:

connection.setAutoCommit(false);

This tells the connection that it should not commit each statement individually, but instead wait for an explicit call to the commit() method.

4. Create a new Statement object to execute your SQL queries:

Statement statement = connection.createStatement();

5. Execute your SQL queries inside a try-catch block. Here's an example that inserts two rows into a table:

try {
    statement.executeUpdate("INSERT INTO mytable (name, age) VALUES ('Alice', 25)");
    statement.executeUpdate("INSERT INTO mytable (name, age) VALUES ('Bob', 30)");
    connection.commit();
} catch (SQLException e) {
    connection.rollback();
    e.printStackTrace();
}

The executeUpdate() method executes the SQL queries and returns the number of affected rows. The commit() method tells the connection to commit the changes made in the transaction. If an exception is thrown, the rollback() method is called to undo any changes made in the transaction.

6. Close the Statement and Connection objects:

statement.close();
connection.close();

This frees up any resources used by the objects.

That's it! With these steps, you can use JDBC transactions in your Java code to group together a set of database operations into a single transaction that either succeeds or fails as a whole.