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

        Class.forName("org.postgresql.Driver");
        connection = DriverManager.getConnection(
        "jdbc:postgresql://localhost:5432/","postgres", "12345");


        Statement statement = connection.createStatement();
        statement.execute("CREATE DATABASE mydb");
        //now I hav to connect to mydb

        connection.close();
    } catch (ClassNotFoundException ex) {
        Logger.getLogger(OracleToPostgres.class.getName()).log(Level.SEVERE, null, ex);
    }catch (SQLException ex) {
        Logger.getLogger(OracleToPostgres.class.getName()).log(Level.SEVERE, null, ex);
    }
}