Help Java Buffer Problem

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1. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 51)
        public final class YANBuffer
                           ^^^^^^^^^
The public type YANBuffer must be defined in its own file
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2. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 96)
        return YANBufferData.GET_INSTANCE().getBufferNpc(npc.getNpcId());
                                                             ^^^^^^^^
The method getNpcId() is undefined for the type L2Npc
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3. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 125)
        activeChar.clearBypass();
                   ^^^^^^^^^^^
The method clearBypass() is undefined for the type L2PcInstance
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4. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 149)
        activeChar.addBypass2(html.substring(start, finish2).trim());
                   ^^^^^^^^^^
The method addBypass2(String) is undefined for the type L2PcInstance
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5. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 153)
        activeChar.addBypass(html.substring(start, finish).trim());
                   ^^^^^^^^^
The method addBypass(String) is undefined for the type L2PcInstance
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6. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 197)
        Long amount = items.get(item.getValue().item.getItemId());
                                                     ^^^^^^^^^
The method getItemId() is undefined for the type L2Item
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7. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 202)
        items.put(item.getValue().item.getItemId(), amount + item.getValue().amo
unt);
                                       ^^^^^^^^^
The method getItemId() is undefined for the type L2Item
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8. ERROR in \YANModPack\YANBuffer\Yanbuffer.java (at line 208)
        buff.skill.getEffects(playable, playable);
        ^^^^^^^^^^
L2Skill cannot be resolved to a type
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9. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANBu
ffer\YANBufferData.java (at line 43)
        import com.l2jserver.gameserver.datatables.NpcTable;
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The import com.l2jserver.gameserver.datatables.NpcTable cannot be resolved
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10. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 44)
        import com.l2jserver.gameserver.datatables.SkillTable;
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The import com.l2jserver.gameserver.datatables.SkillTable cannot be resolved
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11. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 47)
        import com.l2jserver.gameserver.model.skills.L2Skill;
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The import com.l2jserver.gameserver.model.skills.L2Skill cannot be resolved
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12. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 57)
        protected final L2Skill skill;
                        ^^^^^^^
L2Skill cannot be resolved to a type
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13. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 62)
        protected Buff(String ident, L2Skill skill, Element elem)
                                     ^^^^^^^
L2Skill cannot be resolved to a type
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14. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 65)
        this.skill = skill;
        ^^^^^^^^^^
L2Skill cannot be resolved to a type
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15. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 388)
        L2Skill skill = SkillTable.getInstance().getInfo(skillId, skillLevel);
        ^^^^^^^
L2Skill cannot be resolved to a type
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16. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 388)
        L2Skill skill = SkillTable.getInstance().getInfo(skillId, skillLevel);
                        ^^^^^^^^^^
SkillTable cannot be resolved
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17. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 432)
        L2NpcTemplate npc = NpcTable.getInstance().getTemplate(npcId);
                            ^^^^^^^^
NpcTable cannot be resolved
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18. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\YANBufferData.java (at line 439)
        _bufferNpcs.put(npc.getNpcId(), new BufferNpc(npc, curElem));
                            ^^^^^^^^
The method getNpcId() is undefined for the type L2NpcTemplate
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19. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\util
\ItemRequirement.java (at line 38)
        this.placeholder.addChild("id", String.valueOf(item.getItemId())).addChi
ld("icon", item.getIcon()).addChild("name", item.getName()).addChild("amount", S
tring.valueOf(amount));
                                                            ^^^^^^^^^
The method getItemId() is undefined for the type L2Item
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20. ERROR in C:\Users\Administrator\Desktop\L2\game\data\scripts\YANModPack\YANB
uffer\NpcAI.java (at line 49)
        String specificNpcHtml = npc.getNpcId() + ".html";
                                     ^^^^^^^^
The method getNpcId() is undefined for the type L2Npc
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20 problems (20 errors)
The public type YANBuffer must be defined in its own file
L2Skill cannot be resolved to a type
The import com.l2jserver.gameserver.datatables.NpcTable cannot be resolved
The import com.l2jserver.gameserver.datatables.SkillTable cannot be resolved
The import com.l2jserver.gameserver.model.skills.L2Skill cannot be resolved
The method getNpcId() is undefined for the type com.l2jserver.gameserver.model.a
ctor.L2Npc
The method clearBypass() is undefined for the type com.l2jserver.gameserver.mode
l.actor.instance.L2PcInstance
The method addBypass2(java.lang.String) is undefined for the type com.l2jserver.
gameserver.model.actor.instance.L2PcInstance
The method addBypass(java.lang.String) is undefined for the type com.l2jserver.g
ameserver.model.actor.instance.L2PcInstance
The method getItemId() is undefined for the type com.l2jserver.gameserver.model.
items.L2Item
The method getItemId() is undefined for the type com.l2jserver.gameserver.model.
items.L2Item
L2Skill cannot be resolved to a type
L2Skill cannot be resolved to a type
L2Skill cannot be resolved to a type
L2Skill cannot be resolved to a type
SkillTable cannot be resolved
NpcTable cannot be resolved
The method getNpcId() is undefined for the type com.l2jserver.gameserver.model.a
ctor.templates.L2NpcTemplate
The method getItemId() is undefined for the type com.l2jserver.gameserver.model.
items.L2Item
The method getNpcId() is undefined for the type com.l2jserver.gameserver.model.a
ctor.L2Npc