Array Manipulator 91/100

package Lists;

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class ArrayManipulator {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		List<Integer> numbers = Arrays.stream(scanner.nextLine().split(" ")).map(Integer::parseInt)
				.collect(Collectors.toList());

		while (true) {
			List<String> command = Arrays.stream(scanner.nextLine().split(" ")).collect(Collectors.toList());

			if (command.get(0).equals("print")) {
				System.out.println(Arrays.toString(numbers.toArray()));
				return;
			}
			GetResult(numbers, command);
		}
	}

	static void GetResult(List<Integer> numbers, List<String> command) {
		switch (command.get(0)) {
		case "add":
			numbers.add(Integer.parseInt(command.get(1)), Integer.parseInt(command.get(2)));
			break;
		case "addMany":
			AddManyNum(numbers, command);
			break;
		case "contains":
			ContainsNum(numbers, command);
			break;
		case "remove":
			numbers.remove(Integer.parseInt(command.get(1)));
			break;
		case "shift":
			ShiftNum(numbers, command);
			break;
		case "sumPairs":
			sumPairs(numbers);
			break;
		}
	}

	static void ShiftNum(List<Integer> numbers, List<String> command) {
		for (int i = 0; i < Integer.parseInt(command.get(1)); i++) {
			numbers.add(numbers.get(0));
			numbers.remove(0);
		}
	}

	static void AddManyNum(List<Integer> numbers, List<String> command) {
		for (int i = command.size() - 1; i >= 2; i--) {
			numbers.add(Integer.parseInt(command.get(1)), Integer.parseInt(command.get(i)));
		}
	}

	static void ContainsNum(List<Integer> numbers, List<String> command) {
		int specialNumber = Integer.parseInt(command.get(1));
		boolean isTrue = true;
		for (int i = 0; i < numbers.size(); i++) {
			if (numbers.get(i) == specialNumber) {
				System.out.println(i);
				isTrue = false;
				break;
			}
		}
		if (isTrue) {
			System.out.println("-1");
		}
	}

	static void sumPairs(List<Integer> numbers) {
		if (numbers.size() % 2 == 0) {
			for (int i = 0; i < numbers.size(); i++) {

				int sum = numbers.get(i) + numbers.get(i + 1);
				numbers.set(i, sum);
				numbers.remove(i + 1);
			}
		} else {
			for (int i = 0; i < numbers.size() - 1; i++) {
				int sum = numbers.get(i) + numbers.get(i + 1);
				numbers.set(i, sum);
				numbers.remove(i + 1);
			}
		}
	}
}