Android从嵌套的Arraylist中删除项目给出错误并发修改异常

I am new in android. I want to remove item from Arraylist inside Arraylist. But when i removed particular item its given me an error 'ConcurrentModificationException'. So how can i handle it or if any other solution possible then please suggest me to solve this error. i am posting my code.I am new in android. I want to remove item from