Strange code behaviour

I post here because i am literally confused by what happens when my code executes. Read comments in code please.
I have snippets of code:

QuestManager.java

Code:

package quest;
import java.util.HashMap;
import java.util.UUID;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDeathEvent;
import org.bukkit.event.player.PlayerJoinEvent;
import osl.First.Main;
import stats.Statistics;
public class QuestManager implements Listener {
    private UUID playerID = null; //player's UUID
    private Player player = null; //player's object
    HashMap<UUID, QuestManager> playerQuests = Main.getQuests(); //get Main instance for static hashmap containing players and their quests
    private Quest1 quest1 = null; //quest1 instance within class
   
    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent event) {
        player = event.getPlayer(); //set player field to joined player's object
        if (!(playerQuests.containsKey(player.getUniqueId()))) { //check if player is in hashmap
            this.quest1 = new Quest1(player.getUniqueId(), "The beginning", "The description", "You've begun your first quest!", "Your first quest ends here. Good luck!"); //assign quest1 field if he isnt in hashmap
            playerQuests.put(player.getUniqueId(), this); //insert quest for player
            player.sendMessage("Quests have been assigned.");
            playerQuests.get(player.getUniqueId()).quest1.completeQuest(); //this code executes when player joins after enabling plugin
        }
        else
        {
            player.sendMessage("You're already in hashmap."); //this message gets displayed
            playerQuests.get(player.getUniqueId()).quest1.completeQuest(); //but for some reason this code doesn't execute
        }
    }
}

Quest1.java

Code:

package quest;
import java.util.UUID;
import org.bukkit.Bukkit;
import org.bukkit.Material;
import org.bukkit.entity.Entity;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Player;
import org.bukkit.inventory.ItemStack;
public class Quest1 implements IQuest {
    public UUID playerID;
    private String questName = null;
    private String questDescription = null;
    private String beginMessage = null;
    private String completeMessage = null;
    public Player player;
    private boolean isFinished = false;
    private boolean isActive = false;
   
    public Quest1(UUID id, String qName, String qDesc, String bMessage, String cMessage) {
        questName = qName;
        questDescription = qDesc;
        beginMessage = bMessage;
        completeMessage = cMessage;
        this.playerID = id;
        this.player = Bukkit.getPlayer(id);
       //some code..
    }
    public void completeQuest() {
        player.sendMessage(completeMessage);
        player.getInventory().addItem(new ItemStack(Material.STONE, 1));
    }

completeQuest() is only executed when player wasn't added yet to hashmap. If he was added, it just displays message "You're already in hashmap" and doesnt execute this function. Why?

 

Code:java

HashMap<UUID, QuestManager> playerQuests = Main.getQuests(); //get Main instance for static hashmap containing players and their quests

Shoudn't this be static?

Code:java

playerQuests.put(player.getUniqueId(), this);

I guess you need to put quest1 in the HashMap, this way everybody shares 'this.quest1'

Not sure if this fixes your problem, but still helps you on the right tracks.