Solution Review: Removing Duplicates From an ArrayList

import java.util.ArrayList;
class Duplicates
{
    public static void main(String args[])
    {
        ArrayList<String> colours = new ArrayList<String>();
        // Adding the values
        colours.add("blue");
        colours.add("blue");
        colours.add("red");
        colours.add("yellow");
        colours.add("green");
        colours.add("red");
        colours.add("red");
        colours.add("green");
        colours.add("blue");
        
        // Calling the function removeDuplicates
        removeDuplicates(colours);
        System.out.println(colours);
    }
    // Implementing removeDuplicates function
    public static void removeDuplicates(ArrayList<String> colours)
    {
        for(int i = 0; i < colours.size()-1; i++)
        {
            for(int j = i+1; j< colours.size(); j++)
            {
                if(colours.get(i).equals(colours.get(j)))   // If duplicate found
                {
                    colours.remove(j);      // Removing duplicate
                    j--;                    // Moving one step back           
                }
            }
        }
    }
}