Here is an example where we have created two classes. In the first class, we have created a database connection method and in another class, we have invoked the connection method and set up the connection.

import java.sql.*;

class Connect {
public Connection connectToDatabase(){
Connection con=null;
try{
Class.forName("com.mysql.jdbc.Driver");
 con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","root");
}
catch(Exception e){}
return con;
}
}

class DatabaseConnection
{
    public static void main(String[] args) 
    {
        try{
        Connect c=new Connect();
        Connection conn=c.connectToDatabase();
        Statement st=conn.createStatement();
        ResultSet rs=st.executeQuery("Select * from data");
        while(rs.next()){
            System.out.println(rs.getString("name")+"\t"+rs.getString("address"));
        }
        }
        catch(Exception e){
        System.out.println(e);
        }
    }
}