Question: Write a method that removes the duplicate elements from an array list of integers using the following header:
public static void removeDuplicate(ArrayList list)

Write a test program that prompts the user to enter 10 integers to a list and displays the distinct integers in their input order separated by exactly one space.

import java.util.Scanner;
import java.util.ArrayList;
public class RemoveDuplicate {
  public static void main(String[] args) {
    System.out.print("Enter ten integers: ");
    ArrayList<Integer> list = new ArrayList<>();
    Scanner input = new Scanner(System.in);
    for (int i = 0; i < 10; i++) {
      list.add(input.nextInt());
    }
    removeDuplicate(list);
    
    System.out.print("The distinct integers are ");
    for (int i = 0; i < list.size(); i++)
      System.out.print(list.get(i) + " ");
  }
  public static void removeDuplicate(ArrayList<Integer> list) {
    ArrayList<Integer> temp = new ArrayList<>();
    for (int i = 0; i < list.size(); i++)
      if (!temp.contains(list.get(i)))
        temp.add(list.get(i));
    list.clear();
    for (int i = 0; i < temp.size(); i++)
      list.add(temp.get(i));
  }
}

Solution 2:

import java.util.Scanner;
import java.util.ArrayList;

public class RemoveDuplicate {
	/** Main method */
	public static void main(String[] args) {
		// Create a scanner
		Scanner input = new Scanner(System.in);

		// Create an ArrayList
		ArrayList<Integer> list = new ArrayList<Integer>();

		// Prompt ther user to enter 10 integers
		System.out.print("Enter 10 integers: ");
		for (int i = 0; i < 10; i++) {
			list.add(input.nextInt());
		}

		// Invoke removeDuplicate method
		removeDuplicate(list);

		// Display the distinct integers
		System.out.print("The distinct integers are ");
		for (int i = 0; i < list.size(); i++) {
			System.out.print(list.get(i) + " ");
		}
		System.out.println();
	}

	public static void removeDuplicate(ArrayList<Integer> list) {
		for (int i = 0; i < list.size() - 1; i++) {
			for (int j = i + 1; j < list.size(); j++) {
				if (list.get(i) == list.get(j))
					list.remove(j);
			}
		}
		for (int i = 0; i < list.size() - 1; i++) {
			for (int j = i + 1; j < list.size(); j++) {
				if (list.get(i) == list.get(j))
					list.remove(j);
			}
		}		
	}
}

Output:

Sample Run 1
Enter ten integers: 34 5 3 5 6 4 33 2 2 4
The distinct integers are 34 5 3 6 4 33 2

Sample Run 2
Enter ten integers: 3 3 4 4 1 1 2 2 5 5
The distinct integers are 3 4 1 2 5

Sample Run 3
Enter ten integers: 1 2 2 3 4 5 6 7 8 8
The distinct integers are 1 2 3 4 5 6 7 8

Sample Run 4
Enter ten integers: 5 4 3 2 65 4 4 5 1 5
The distinct integers are 5 4 3 2 65 1