How to use my own .jar as an api/library?

Question

I am using intellij IDEA and I have followed all instructions I was told to export my project as a .jar. It says that I am not able to use my jar as an api and call the methods. HEre's my jar:

` package me.JBoss925.com;

 import com.sun.org.apache.xerces.internal.xs.StringList;
 import org.bukkit.Material;
 import org.bukkit.entity.Player;
 import org.bukkit.event.block.Action;
 import org.bukkit.event.player.AsyncPlayerChatEvent;
 import org.bukkit.event.player.PlayerInteractEvent;
 import org.bukkit.event.player.PlayerJoinEvent;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.bukkit.potion.PotionEffect;
 import org.bukkit.potion.PotionEffectType;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.UUID;

 /**
  * Created by JBoss925 on 4/11/14.
  * Made for beginners and people who want to spend less time on code.
  * If you can see this please tell me how you were able to decompile this.
  */
 public class api extends JavaPlugin{

     public static AsyncPlayerChatEvent chat;
     public static PlayerJoinEvent join;
     public static PlayerInteractEvent pie;

     public static void setKilled(Player victim, boolean killed){
         if(killed == true){
             victim.setHealth(0.0);
         }
     }

     public static void openInventory(Player player, Inventory inventory){
         player.openInventory(inventory);
     }

     public static void closeInventory(Player player, Inventory inventory){
         if(player.getOpenInventory().equals(inventory)){
             player.closeInventory();
         }
     }

     public static void tellPlayer(Player receiver, String message){
         receiver.sendMessage(message);
     }

     public static void replaceCurseWords(boolean allowed){
         if(allowed == true){
             return;
         }
         if(allowed == false){
             if(chat.getMessage().contains("crap")){
                 chat.getMessage().replace("crap", "flip");
             }
             if(chat.getMessage().contains("good")){
                 chat.getMessage().replace("good", "poop");
             }
             if(chat.getMessage().contains("damn")){
                 chat.getMessage().replace("damn", "darn");
            }
             if(chat.getMessage().contains("douche")){
                 chat.getMessage().replace("douche", "friend");
             }
         }
     }

     public static void addPotion(PotionEffectType potionEffectType, Player player,      Integer time, Integer level){
         player.addPotionEffect(new PotionEffect(potionEffectType, level, time));
     }

     public static void playerAddUUIDList(Player player, List list){
         UUID i = player.getUniqueId();
         list.add(i);
     }

     public static void playerAddUUIDList(Player player, ArrayList arrayList){
      UUID i = player.getUniqueId();
         arrayList.add(i);
     }

     public static void performCommand(Player player, String command){
         player.performCommand(command);
     }

     public static void playerSetFire(Player victim, Integer ticksIfEnabled, boolean enabled){
         if(enabled == true){
             victim.setFireTicks(ticksIfEnabled);
         }
         if(enabled == false){
             victim.setFireTicks(0);
         }
     }








 }

`

Answer 1

To add jar file to you project classpath follow the steps here

Go to Project-> Libraries and add the  folder that has the jars. all in this folder will be added to classpath.

These jar files will be working as api.

Answer 2

Using jdk create the jar including all the required classes and then include it in the class path. you should be able to import your classes as required.