Java - Avoid/Solve StackOverFlow

this is the code

import java.util.ArrayList;
import java.util.List;

public class ScheduleGenerator {
    public static void main(String[] args) {
        List<Team> teams = new ArrayList<>();
        int numTeams = 9;
        for (int i = 1; i <= numTeams; i++) {
            teams.add(new Team("Team " + i));
        }
        String[] pistes = {"Piste A", "Piste B", "Piste C", "Piste D", "Piste E", "Piste F"};
        List<Round> rounds = generateSchedule(teams);

        for (Round round : rounds) {
            System.out.println("Round " + round.getNumber());
            List<Match> matches = round.getMatches();
            for (int i = 0; i < matches.size(); i++) {
                Match match = matches.get(i);
                String piste = pistes[i];
                System.out.println(piste + " " + match.getTeam1().getName() + " vs " + match.getTeam2().getName());
            }
            System.out.println();
        }
    }

    public static List<Round> generateSchedule(List<Team> teams) {
        int numTeams = Math.round(teams.size());
        int numRounds = numTeams;
        int halfSize = numTeams / 2;

        List<Team> list = new ArrayList<>(teams);

        int listSize = list.size();

        List<Round> rounds = new ArrayList<>();

        if (numTeams % 2 != 0) {
            teams.add(new Team("Rest"));
            numTeams++;
        }


        for (int round = 0; round < numRounds; round++) {
            Round currentRound = new Round(round);
            List<Match> matches = new ArrayList<>();
            int teamIdx = round % listSize;
            Team team1 = list.get(teamIdx);
            Team team2 = teams.get(numTeams - 1);
            matches.add(new Match(team1, team2));
            for (int i = 1; i < halfSize; i++) {
                int firstTeam = (round + i) % listSize;
                int secondTeam = (round + listSize - i) % listSize;
                matches.add(new Match(list.get(firstTeam), list.get(secondTeam)));
            }
            currentRound.setMatches(matches);
            rounds.add(currentRound);
        }

        return rounds;
    }
}

class Team {
    private String name;

    public Team(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        return name;
    }
}

class Round {
    private int number;
    private List<Match> matches;

    public Round(int number) {
        this.number = number;
        this.matches = new ArrayList<>();
    }

    public int getNumber() {
        return number;
    }

    public void addMatch(Match match) {
        matches.add(match);
    }
    public void setMatches(List<Match> matches) {
        this.matches = matches;
    }

    public List<Match> getMatches() {
        return matches;
    }

    public boolean hasMatch(Team team1, Team team2) {
        for (Match match : matches) {
            if ((match.getTeam1() == team1 && match.getTeam2() == team2) ||
                    (match.getTeam1() == team2 && match.getTeam2() == team1)) {
                return true;
            }
        }
        return false;
    }
}

class Match {
    private Team team1;
    private Team team2;

    public Match(Team team1, Team team2) {
        this.team1 = team1;
        this.team2 = team2;
    }

    public Team getTeam1() {
        return team1;
    }

    public Team getTeam2() {
        return team2;
    }
}

The output needs to be like this

Round 0
Piste A Team 1 vs Team 9
Piste B Team 2 vs Team 8
Piste C Team 3 vs Team 7
Piste D Team 4 vs Team 6
Piste E Rest vs Team 5

Round 1
Piste A Team 1 vs Team 9
Piste B Team 2 vs Team 8
Piste C Team 3 vs Team 7
Piste D Team 4 vs Team 6
Piste E Rest vs Team 5

Round 2
Piste A Team 9 vs Team 8
Piste B Team 1 vs Team 7
Piste C Team 2 vs Team 6
Piste D Team 3 vs Team 5
Piste E Rest vs Team 4

Round 3
Piste A Team 8 vs Team 7
Piste B Team 9 vs Team 6
Piste C Team 1 vs Team 5
Piste D Team 2 vs Team 4
Piste E Rest vs Team 3

Round 4
Piste A Team 7 vs Team 6
Piste B Team 8 vs Team 5
Piste C Team 9 vs Team 4
Piste D Team 1 vs Team 3
Piste E Rest vs Team 2

Round 5
Piste A Team 6 vs Team 5
Piste B Team 7 vs Team 4
Piste C Team 8 vs Team 3
Piste D Team 9 vs Team 2
Piste E Rest vs Team 1

Round 6
Piste A Team 5 vs Team 4
Piste B Team 6 vs Team 3
Piste C Team 7 vs Team 2
Piste D Team 8 vs Team 1
Piste E Rest vs Team 9

Round 7
Piste A Team 4 vs Team 3
Piste B Team 5 vs Team 2
Piste C Team 6 vs Team 1
Piste D Team 7 vs Team 9
Piste E Rest vs Team 8

Round 8
Piste A Team 3 vs Team 2
Piste B Team 4 vs Team 1
Piste C Team 5 vs Team 9
Piste D Team 6 vs Team 8
Piste E Rest vs Team 7

Round 9
Piste A Team 2 vs Team 1
Piste B Team 3 vs Team 9
Piste C Team 4 vs Team 8
Piste D Team 5 vs Team 7
Piste E Rest vs Team 6

but as you can see in the first bit of the code here

for (Round round : rounds) {
            System.out.println("Round " + round.getNumber());
            List<Match> matches = round.getMatches();
            for (int i = 0; i < matches.size(); i++) {
                Match match = matches.get(i);
                String piste = pistes[i];
                System.out.println(piste + " " + match.getTeam1().getName() + " vs " + match.getTeam2().getName());
            }
            System.out.println();
        }

this loop makes it that the maximum index is 4 that means that every time I run this code it will be missing Piste E and the output will be something like this

Round 0
Piste A Team 1 vs Rest
Piste B Team 2 vs Team 9
Piste C Team 3 vs Team 8
Piste D Team 4 vs Team 7

Round 1
Piste A Team 2 vs Rest
Piste B Team 3 vs Team 1
Piste C Team 4 vs Team 9
Piste D Team 5 vs Team 8

Round 2
Piste A Team 3 vs Rest
Piste B Team 4 vs Team 2
Piste C Team 5 vs Team 1
Piste D Team 6 vs Team 9

Round 3
Piste A Team 4 vs Rest
Piste B Team 5 vs Team 3
Piste C Team 6 vs Team 2
Piste D Team 7 vs Team 1

Round 4
Piste A Team 5 vs Rest
Piste B Team 6 vs Team 4
Piste C Team 7 vs Team 3
Piste D Team 8 vs Team 2

Round 5
Piste A Team 6 vs Rest
Piste B Team 7 vs Team 5
Piste C Team 8 vs Team 4
Piste D Team 9 vs Team 3

Round 6
Piste A Team 7 vs Rest
Piste B Team 8 vs Team 6
Piste C Team 9 vs Team 5
Piste D Team 1 vs Team 4

Round 7
Piste A Team 8 vs Rest
Piste B Team 9 vs Team 7
Piste C Team 1 vs Team 6
Piste D Team 2 vs Team 5

Round 8
Piste A Team 9 vs Rest
Piste B Team 1 vs Team 8
Piste C Team 2 vs Team 7
Piste D Team 3 vs Team 6

Round 9
Piste A Team 1 vs Rest
Piste B Team 2 vs Team 9
Piste C Team 3 vs Team 8
Piste D Team 4 vs Team 7

I am just really ignorant with this type of error it's been almost 3 days with me trying to figure out a thing. Thanks in advance

Just Figure it out int halfSize = numTeams / 2; should be added by one like this int halfSize = numTeams / 2 +1;