Question

[Tests problem solving and a little bit of Java language] Write a Java method removeDuplicates that removes all duplicates in a given list. Assume the following:

a. The method accepts an object of type List

b. The return type of the method is void

c. Duplicates are determined using the equals() method (rather than by the == operator)

Your implementation of removeDuplicates should handle, in an appropriate way, the case in which a null List is passed in to the method.
Test your method by writing code in a main method, which does the following:

a. It creates an instance of List and loads it with the following String values:{“good”, “better”, “best”, “best”, “first”, “last”, “last”, “last”,”good”}

b. It invokes the removeDuplicatesMethod, passing in this instance of List

c. It outputs the modified list to the console

Answer 1

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class RemoveDuplicatesArrayList {

    public static void removeDuplicates(List<String> list) {
        for (int i = 0; i < list.size(); ++i) {
            int count = 0;
            for (int j = 0; j < i; ++j) {
                if (list.get(j).equals(list.get(i))) {
                    count++;
                }
            }
            if (count >= 1) {
                list.remove(i);
                i--;
            }
        }
    }

    public static void main(String[] args) {
        List<String> list = new ArrayList<String>(Arrays.asList("good", "better", "best", "best", "first", "last", "last", "last", "good"));
        removeDuplicates(list);
        System.out.println(list);
    }
}

[good, better, best, first, last] Process finished with exit code o