Pool de conexões

Bom dia Rodrigo, qual pacote da sua classe ?

package br.com.caelum.jdbc;

import java.sql.Connection;
import java.sql.SQLException;
import javax.sql.DataSource;

import org.hsqldb.jdbc.JDBCPool;

public class ConnectionPool {
    private DataSource dataSource;

    public ConnectionPool() {
        JDBCPool pool = new JDBCPool();
        pool.setURL("jdbc:hsqldb:hsql://localhost/loja-virtual");
        pool.setUser("SA");
        pool.setPassword("");
        this.dataSource = pool;
    }

    public Connection getConnection() throws SQLException {
        Connection connection = dataSource.getConnection();
        return connection;
    }
}

Não conheço a classe JDBCPool mas se for do pacote org.hsqldb.jdbc, pela documentação está:

public JDBCPool(int size)
Creates a connection pool with the given maximum size. The database and connection settings are made before the getConnection() is called.
Parameters:
size - int maximum size of the pool