Design/Improvement Question

Question

Hi!
I've recently been tasked with making sure that all of the connection to a certain account are set up when we moved it to a new oracle server/instance(done by comparing the results of several queries). I've developed a small program to help make my life easier and to gain a little knowledge in java. The thing works, I'm just curious as to if there is a better way of doing the task. Currently here is my process:
Using System.out and System.in
Get the account name I'm testing from user (which will be me most of the time but in-case I decide to share my toy).
Get username and password(99.999% of the time it'll be a default username/pw that we have access to I just added the option in-case it's for a production server that the default doesn't work on).
Get the two instances to compare.
Create two urls for JDBC based on the instance
Start running the queries(Prepared Statements) that return Lists<String>
Compare the two lists
Output the differences into an excel file using apache POI.
So my question is this; Is my design ok? (Specifically my compare method is what I'm unsure about) Do you have any suggestions for improvement? How would you do this differently? (Swing is off the table for now, maybe as another learning session I'll try to do the same thing but with a gui)
I'm fairly new to java programming, which is probably obvious, so I appreciate all feedback and criticisms.
public static void main(String args[]){
     GetInformationFromUser first = new GetInformationFromUser();
     //get info from the user
     first.setAccount();
     first.setInstance();
     first.setUserNameandPW();
     //do same for a second account
     //Create 2 connections
     DatabaseConnection dbc = new DatabaseConnection();
     Connection firstCon = dbc.createURL(first.getInstance(), first.getUserName(), first.Password());
     Connection secCon = dbc.createURL(sec.getInstance(), sec.getUserName(), sec.Password());
     //open up the database connection and run the queries
     List<String> firstList = dbc.callQuery1(firstCon, first.getAccount());
     List<String> secList = dbc.callQuery1(secCon, sec.getAccount());
     List<String> differences = dbc.compare(firstList, secList);
     dbc.output(differences);
}Then my compare method is similar to this:
public class DatabaseConnection {
    public List<String> callQuery1(Connection con, String account){
        //Run a prep statement
        //use the ResultSet to fill a List
        //return the list
    public List<String> callQuery2(Connection con, String account){
        //Same Idea as 1
    public List<String> callQuery3(Connection con, String account){
        //Same Idea as 1
    public List<String> compare(List<String> first, List<String> second, String firstInstance, String secInstance){
        List<String> differences = new ArrayList<String>();
        for(String s : first){
            if(second.contains(s)){
                //do nothing (don't care about similarities only what is missing)
            }else{
                differences.add(firstInstance +" has "+ s +" that "+ secInstance +" doesn't");
         for(String s : second){
             if(first.contains(s)){
                 //do nothing (don't care about similarities; only what is missing)
              }else{
                 differences.add(secInstance + " has " + s + " that " + firstInstance + " doesn't");
        return differences;
}Thanks!

Answer 1

The design seems fine.
I would suggest that you use Set instead of List as Set ignores the order of entries. It is also simple to find the differences using sets by taking a copy and doing removeAll()