NullPointerException

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DBConnection {
private Connection conn;
private Statement st;
private ResultSet rs;
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/javatest";
// Database credentials
static final String USER = "root";
static final String PASS = "";
public void DBConnection() {
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
st = conn.createStatement();
} catch (ClassNotFoundException | SQLException ex) {
System.out.println("Error : " + ex);
}
}
public void getData() {
try {
String query = "select * from person";
rs = st.executeQuery(query);
System.out.println("Records from the database");
while (rs.next()) {
int id = rs.getInt("id");
String name = rs.getString("name");
String age = rs.getString("age");
System.out.println("Id: " + id + "Name : " + name + "Age : " + age);
}
} catch (Exception ex) {
System.out.println(ex);
}
}
}