import java.util.*;

public class Main_testRemoveElement
{
	public static void main(String[] args) 
	{
		List<Integer> dataList;
		dataList = new ArrayList<>();
		for(int i=0;i<10;i++)
			dataList.add(i*i);

		System.out.println(dataList); //Output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
		
		
		insert(dataList,64,99); //insert value 99 after the element which equals 64
		System.out.println(dataList); //Output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 99, 81]
		
		remove(dataList,64); //remove element which equals 64 
		System.out.println(dataList);	//Output: [0, 1, 4, 9, 16, 25, 36, 49, 99, 81]
	}

	private static void insert(List<Integer> dataList, int preValue, int value) 
	{
//		for (int i=0;i<dataList.size();i++)
//			if (dataList.get(i)==preValue)
//				dataList.add(i+1,value);
		
		int idx=0;
		for (Integer e:dataList) //Exception : java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification
		{
			if (e==preValue)
				dataList.add(idx+1,value);
			idx++;
		}

//		Iterator<Integer> itr = dataList.iterator();
//		int idx=0;
//		while (itr.hasNext()){
//			Integer e = itr.next();
//			if (e==preValue)
//				dataList.add(idx+1,value);
//			idx++;
//		}
	
	}	
	
	private static void remove(List<Integer> dataList, int value) 
	{
		for (int i=0;i<dataList.size();i++)
			if (dataList.get(i)==value)
				dataList.remove(i);
		
		int idx=0;
		for (Integer e:dataList) //Exception : java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification
		{
			if (e==value)
				dataList.remove(idx);
			idx++;
		}
		
//		Iterator<Integer> itr = dataList.iterator();
//		int idx=0;
//		while (itr.hasNext()){
//			Integer e = itr.next();
//			if (e==value)
//				dataList.remove(idx);
//			idx++;
//		}
		
	}	
}