Defining Entities to connect mysql database to a java project

Question

I have a mysql database that I want to connect to my Java (Spring MVC) project (I'm using IntelliJ). As I learned, I defined the entities and repositories in IntelliJ equivalent to the database's tables. However, I wrote a short code that is able to connect to my datatbase, run sql queries and save/print the query's results:

public static void main(String args[]){
    try{
        Class.forName("com.mysql.jdbc.Driver"); // Connecting to mySql
        Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/theprocess?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC","root","root");
        // Connecting to our database
        Statement stmt = con.createStatement();
        // Object that allows executing SQL queries
        ResultSet rs = stmt.executeQuery("select * from clients");
        // Storing the query's result
        while(rs.next())
            System.out.println(rs.getInt(1)+"  "+rs.getString(2)+"  "+rs.getString(3));
        // Defines which columns to print
        con.close(); // Closing the connection;
    }catch(Exception e){ System.out.println(e);}
}    

So my question is, do I even need the entities and repositories if I have that code? Thanks for your help :)