This example show you how to use the `CallableStatement.wasNull()` method call to see if the last `OUT` parameter has a value of SQL `NULL`.

“`java
package org.kodejava.jdbc;

import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.CallableStatement;
import java.sql.DriverManager;
import java.sql.Types;
import java.sql.SQLException;

public class WasNullExample {
private static final String URL = "jdbc:mysql://localhost/kodejava";
private static final String USERNAME = "kodejava";
private static final String PASSWORD = "s3cr*t";

public static void main(String[] args) {
try (Connection connection =
DriverManager.getConnection(URL, USERNAME, PASSWORD)) {

// Prepares a call to the sored procedure
String query = "call Get_Product_By_Price2(?, ?)";
CallableStatement cb = connection.prepareCall(query);

// Sets the input parameter
cb.setBigDecimal(1, new BigDecimal("50"));

// Registers the OUT parameter
cb.registerOutParameter(2, Types.VARCHAR);

// Executes the query
cb.executeQuery();

// Gets the OUT parameter value
cb.getString(2);

// Checks if the last OUT parameter has the value of SQL NULL.
// This method should be called only after calling a getter
// method; otherwise, there is no value to use in determining
// whether it is null or not.
if (cb.wasNull()) {
System.out.println("Product has an SQL NULL value");
} else {
System.out.println("Product: " + cb.getString(2));
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
“`

Here is the stored procedure script we called in the example above.

“`sql
DELIMITER ;;
DROP PROCEDURE IF EXISTS Get_Product_By_Price2;;
CREATE PROCEDURE Get_Product_By_Price2(
IN product_price DECIMAL(10, 2),
OUT product_name VARCHAR(100))
BEGIN
SELECT name
INTO product_name
FROM product
WHERE price = product_price;
END;;
DELIMITER ;
“`

**Maven Dependencies**

“`xml
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
<version>8.4.0</version>
</dependency>
“`

[](https://search.maven.org/search?q=g:%22com.mysql%22%20AND%20a:%22mysql-connector-j%22)