NullPointerException

Hi, when I join to the server, I get this java.lang.NullPointerException: null

PlayerJoinEvent:

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Code:

@EventHandler
    public void join(PlayerJoinEvent e) {
        e.setJoinMessage("");
        Player player = e.getPlayer();
        String nick = player.getName();
        sqm.FirstConnectionInsert(nick);
        return;
    }

sqm.FirstConnectionInsert

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Code:

    public void FirstConnectionInsert(String nick) {
        Connection c = null;
        Statement stmt = null;
        try {
            c = DriverManager.getConnection("jdbc:sqlite:" + main.getDataFolder() + File.separator + "Users.db");
            stmt = c.createStatement();
            String sql = "INSERT OR IGNORE INTO USERS (ID, NICK, KITS, BALANCE, KILLS, DEATH) " +
                    "VALUES (null, '"+ nick + "', 0, 0 , 0, 0 );";
            stmt.executeUpdate(sql);
            stmt.close();
            c.close();
        } catch ( Exception e ) {
             System.err.println( e.getClass().getName() + ": " + e.getMessage() );
             System.exit(0);
        }
    }
   

 

@Clybzotik Can you show us the stack trace with a screenshot?

 

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Code:

[20:42:22] [Server thread/WARN]: java.lang.NullPointerException: null
[20:42:22] [Server thread/WARN]: java.lang.NullPointerException
[20:42:22] [Server thread/WARN]:     at kpvp.main.SQLiteManager.FirstConnectionInsert(SQLiteManager.java:20)
[20:42:22] [Server thread/WARN]:     at kpvp.main.Handler.join(Handler.java:38)
[20:42:22] [Server thread/WARN]:     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[20:42:22] [Server thread/WARN]:     at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
[20:42:22] [Server thread/WARN]:     at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
[20:42:22] [Server thread/WARN]:     at java.lang.reflect.Method.invoke(Unknown Source)
[20:42:22] [Server thread/WARN]:     at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302)
[20:42:22] [Server thread/WARN]:     at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
[20:42:22] [Server thread/WARN]:     at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:500)
[20:42:22] [Server thread/WARN]:     at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:485)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.PlayerList.onPlayerJoin(PlayerList.java:346)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.PlayerList.a(PlayerList.java:166)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.LoginListener.b(LoginListener.java:159)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.LoginListener.e(LoginListener.java:57)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.NetworkManager.a(NetworkManager.java:233)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.ServerConnection.c(ServerConnection.java:140)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:845)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679)
[20:42:22] [Server thread/WARN]:     at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577)
[20:42:22] [Server thread/WARN]:     at java.lang.Thread.run(Unknown Source)
[20:42:23] [Server thread/INFO]: Clybzotik[/127.0.0.1:52814] logged in with entity id 104 at ([world]146.5, 69.0, 247.5)

 

This: c = DriverManager.getConnection("jdbc:sqlite:" + main.getDataFolder() + File.separator + "Users.db");

 

Code:

package kpvp.main;

import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class SQLiteManager {

    private KitPVP main;
    public SQLiteManager(KitPVP main) {
        this.main = main;
    }

    public void FirstConnectionInsert(String nick) {
        Connection c = null;
        Statement stmt = null;
        try {
            Class.forName("org.sqlite.JDBC");
            c = DriverManager.getConnection("jdbc:sqlite:" + main.getDataFolder() + File.separator + "Users.db");
            stmt = c.createStatement();
            String sql = "INSERT OR IGNORE INTO USERS (ID, NICK, KITS, BALANCE, KILLS, DEATH) " +
                    "VALUES (null, '"+ nick + "', 0, 0 , 0, 0 );";
            stmt.executeUpdate(sql);
            stmt.close();
            c.close();
        } catch ( Exception e ) {
             System.err.println( e.getClass().getName() + ": " + e.getMessage() );
             e.printStackTrace();
        }
    }
  
    public boolean TestFirstConnect(String nick) {
        Connection c = null;
        Statement stmt = null;
        try {
            c = DriverManager.getConnection("jdbc:sqlite:" + main.getDataFolder() + File.separator + "Users.db");
            stmt = c.createStatement();
            ResultSet rs = stmt.executeQuery( "SELECT NICK FROM USERS WHERE NICK ='" + nick + "';" );
            if (!rs.isBeforeFirst()) {
                return false;
            }
            stmt.close();
            c.close();
        } catch ( Exception e ) {
             System.err.println( e.getClass().getName() + ": " + e.getMessage() );
             System.exit(0);
        }
        return true;
    }
    public void getPlayerStats(String nick) {
        // Чото будет
        return;
    }
}

 

Yes it exists.

Does anyone know how to fix this?

UPD: @timtower

Removed plugin.getDataFolder from the connection and the error was solved. Apparently the problem is in the inheritance of the main class.