[ÇÖZÜLDÜ]liste.add(eleman) NullPointerException Sorunu

public class Slice { 
  	List<Checker> checkerList; 
  	public int sliceNo; 
  	private boolean hasbrokenChecker=false; 
  	private int brokenChecker_sPlayerNo=Checker.PLAYER_X; 
  	private int locationX=0; 
  	private int locationY=0; 
  	 
  	Slice(int sliceNo) 
  	{ 
  	  this.sliceNo=sliceNo; 
  	} 
  	 
  	public void insertChecker(Checker _c) 
  	{ 
  		if ((_c.getPlayer()==checkerList.get(checkerList.size()-1).getPlayer())||(1>=checkerList.size()-1)) 
  		{ 
  			if((_c.getPlayer()!=checkerList.get(checkerList.size()-1).getPlayer())) 
  			{ 
  				setbrokenChecker(true); 
  				setBrokenChecker_sPlayerNo(checkerList.get(checkerList.size()-1).getPlayer()); 
  				checkerList.remove(1); 
  				 
  				checkerList.add(_c); 
  			} 
  			else checkerList.add(_c); 
  		} 
  		 
  	} 
  	 
  	public List<Checker> getCheckers() 
  	{ 
  		return checkerList;		 
  	} 
  	 
  	public void setLocationSlice() 
  	{ 
  		 
  		  
  		if(sliceNo<7) 
  		{ 
  			locationX=800-(sliceNo*50+180); 
  			locationY=0; 
  		} 
  			 
  		  
  		if((sliceNo>6)&&(sliceNo<13)) 
  		{ 
  			locationX=800-(sliceNo*50+230); 
  			locationY=0; 
  		} 
  			 	 
  		if((sliceNo>12)&&(sliceNo<19)) 
  		{ 
  			locationX=800-((sliceNo-6)*50+230); 
  			locationY=600; 
  		} 
  		if((sliceNo>18)&&(sliceNo<25)) 
  		{ 
  			locationX=800-((sliceNo-12)*50+180); 
  			locationY=600; 
  		} 
    
  	} 
   
  	public boolean getbrokenChecker() { 
  		return hasbrokenChecker; 
  	} 
   
  	public void setbrokenChecker(boolean hasbrokenChecker) { 
  		this.hasbrokenChecker = hasbrokenChecker; 
  	} 
  	public int getLocationX() { 
  		return locationX; 
  	}public void setLocationX(int locationX) { 
  		this.locationX = locationX; 
  	}public void setLocationY(int locationY) { 
  		this.locationY = locationY; 
  	}public int getLocationY() { 
  		return locationY; 
  	} 
   
  	public int getBrokenChecker_sPlayerNo() { 
  		return brokenChecker_sPlayerNo; 
  	} 
   
  	public void setBrokenChecker_sPlayerNo(int brokenChecker_sPlayerNo) { 
  		this.brokenChecker_sPlayerNo = brokenChecker_sPlayerNo; 
  	} 
  }