HT linear probing

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Scanner;

public class solve {

    static class Pair implements Comparable<Pair>{
        private int key;
        private String value;
        public Pair(int key, String value) {
            this.key = key;
            this.value = value;
        }

        public int getKey(){ return this.key;}

        public String getValue() { return this.value;}

        public void setValue(String value) { this.value = value;}
        @Override
        public boolean equals(Object obj) {
            if(obj != null) {
                if(obj instanceof Pair) {
                    return ((Pair)obj).getKey() == this.getKey();
                }
            }
            return false;
        }

        @Override
        public String toString() {
            return "<"+this.key+", "+this.value+">";
        }

        @Override
        public int compareTo(Pair o) {
            if (this.getKey() < o.getKey()) {
                return -1;
            }
            if (this.getKey() > o.getKey()) {
                return 1;
            }
            return this.getValue().compareTo(o.getValue());
        }
    }
    static class hashTable{

        private Pair table[];
        private HashMap<Integer, String> persons;
        private int sz;
        private int elements;

        public hashTable(int size) {
            table = new Pair[size];
            persons = new HashMap<>();
            sz = size;
            this.elements = 0;
        }

        private int getIndex(int key) {
            return key%sz;
        }

        private void print() {
            System.out.print("[");
            for(int i = 0; i < sz; i++) {
                if(table[i] != null) System.out.print(table[i].toString());
                else System.out.print("null");
                if(i != sz-1) System.out.print(", ");
            }
            System.out.println("]");
        }

        public void put(int key, String value) {
            Pair novo = new Pair(key, value);
            if (this.elements < this.sz) {
                    int idx = this.getIndex(key);

                    while (this.table[idx] != null) {
                        if (this.table[idx].equals(novo)) {
                            this.elements--;
                            persons.remove(key);
                            break;
                        }
                        idx++;
                    }

                    persons.put(key, value);
                    this.table[idx] = novo;
                    this.elements++;

            }
            this.print();
        }

        public void remove(int key) {
            int idx = this.getIndex(key);
            Pair aux = new Pair(key, "");
            int pos = -1;
            while(idx < sz) {
                if(table[idx] != null && table[idx].equals(aux)) pos = idx;
                idx++;
            }

            if(pos != -1) {
                persons.remove(key);
                table[pos] = null;
                this.elements--;
            }

            this.print();
        }

        public void keys() {

            ArrayList aux = new ArrayList();
            aux.addAll(persons.keySet());
            Collections.sort(aux);
            System.out.println(Arrays.toString(aux.toArray()));
        }

        public void values() {
            ArrayList aux = new ArrayList();
            aux.addAll(persons.values());
            Collections.sort(aux);
            System.out.println(Arrays.toString(aux.toArray()));
        }

    }
    private static Scanner sc;
    public static void main(String[] args) {
        sc = new Scanner(System.in);

        int sz = sc.nextInt();
        hashTable table = new hashTable(sz);
        while(true) {
            String action = sc.nextLine();
            String[] choice = action.split(" ");

            if(choice[0].equals("end")) break;
            switch(choice[0]) {
                case "keys":
                    table.keys();
                    break;
                case "remove":
                    table.remove(Integer.parseInt(choice[1]));
                    break;
                case "put":
                    table.put(Integer.parseInt(choice[1]), choice[2]);
                    break;
                case "values":
                    table.values();
                    break;

            }
        }

    }
}