SQL Fiddling in Java

package sqlfiddle;

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

public class Main {

    public static void main(String[] args) {
        Connection c = null;

        try {
            Class.forName("org.postgresql.Driver");
            c = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres",
                    "postgres", "postgres");
            System.out.println("Database open ok");
            System.out.println("Creating table ...");
            createTable(c);
            System.out.println("Inserting a customer ...");
            insert(c, "Théo Morales", "theo.morales@mail.com", 91748274, false);
            System.out.println("Updating customer Théo Morales...");
            update(c, "theo.morales@mail.com", "Théo Martin Morales", null, true);
            System.out.println("Deleting customer Théo Martin Morales...");
            delete(c, "theo.morales@mail.com");
            System.out.println("Dropping table customers...");
            dropTable(c);
        } catch (Exception e) {
            System.err.println(e.getClass().getName() + ": " + e.getMessage());
            System.exit(0);
        }

        if(c != null) {
            try {
                c.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    private static void createTable(Connection c) throws SQLException {
        Statement stmt = c.createStatement();
        String qry = "CREATE TABLE \"JAVA\".customers("
                    + "id SERIAL PRIMARY KEY,"
                    + "name VARCHAR(30) NOT NULL,"
                    + "email VARCHAR(40) UNIQUE NOT NULL,"
                    + "phone_number NUMERIC NOT NULL,"
                    + "verified BOOLEAN DEFAULT(false)"
                    + ");";
        stmt.execute(qry);
        stmt.close();
        System.out.println("Create table ok");
    }

    private static void insert(Connection c, String name, String email, long phoneNumber, boolean verified) throws SQLException {
        Statement stmt = c.createStatement();
        String qry = "INSERT INTO \"JAVA\".customers(name, email, phone_number, verified) "
                    + "VALUES('" + name + "', '" + email + "', " + phoneNumber + ", " + verified + ");";
        stmt.execute(qry);
        stmt.close();
        System.out.println("Insert row ok");
    }

    private static void update(Connection c, String customerEmail, String newName, Long newPhoneNumber, Boolean verified) throws SQLException {
        Statement stmt = c.createStatement();
        String qry = "UPDATE \"JAVA\".customers SET"
                    + (newName != null ? " name = '" + newName + "'" : "")
                    + (newPhoneNumber != null ? ", phone_number = " + newPhoneNumber : "")
                    + (verified != null ? ", verified = " + verified : "")
                    + " WHERE email = '" + customerEmail + "';";
        stmt.executeUpdate(qry);
        stmt.close();
        System.out.println("Update row ok");
    }

    private static void delete(Connection c, String customerEmail) throws SQLException {
        Statement stmt = c.createStatement();
        String qry = "DELETE FROM \"JAVA\".customers WHERE email = '" + customerEmail + "';";
        stmt.execute(qry);
        stmt.close();
        System.out.println("Delete row ok");
    }

    private static void dropTable(Connection c) throws SQLException {
        Statement stmt = c.createStatement();
        stmt.execute("DROP TABLE \"JAVA\".customers;");
        stmt.close();
        System.out.println("Drop table ok");
    }
}