remove elements from for loop vs iterator

foorloopvsiterator.java

package com.java.forloopvsiterator.test;

import java.util.ArrayList;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.List;

public class Main {

    public static void main(String[] args) {

        // show init lists
        println("Initial List");
        printArray(createList());
        println("To Remove List");
        printArray(createToRemoveList());

        // foreach
        testRemoveViaForEachLoop();

        // iterator
        testRemoveViaIterator();
    }

    private static void testRemoveViaIterator() {
        println("Remove testRemoveViaIterator");
        final List<?> array = createList();
        try {
            removeUsingIterator(array, createToRemoveList());
        } catch (final ConcurrentModificationException e) {
            e.printStackTrace();
        }
        printArray(array);
    }

    private static void testRemoveViaForEachLoop() {
        println("Remove removeUsingForeach");
        final List<?> array = createList();
        try {
            removeUsingForeach(array, createToRemoveList());
        } catch (ConcurrentModificationException e) {
            // slurp
        }
        printArray(array);
    }

    private static void removeUsingIterator(final List<?> list, final List<?> toRemove) {
        for (Iterator<?> listIterator = list.iterator(); listIterator.hasNext(); ) {
            final Object o = listIterator.next();
            for (Iterator<?> toRemoveIterator = toRemove.iterator(); toRemoveIterator.hasNext(); ) {
                final Object p = toRemoveIterator.next();
                if (o.equals(p))
                    listIterator.remove();
            }
        }
    }

    private static void removeUsingForeach(final List<?> list, final List<?> toRemove) throws ConcurrentModificationException {
        for (final Object o : list)
            for (final Object p : toRemove)
                if (o.equals(p))
                    list.remove(p);
    }

    private static List<?> createList() {
        final ArrayList<String> strings = new ArrayList<String>();
        for (char letter = 'a'; letter <= 'z'; ++letter)
            strings.add(String.valueOf(letter));
        return strings;
    }

    private static List<?> createToRemoveList() {
        final ArrayList<String> strings = new ArrayList<String>();
        for (char letter = 'e'; letter <= 'q'; ++letter)
            strings.add(String.valueOf(letter));
        return strings;
    }

    private static void printArray(final List<?> list) {
        for (final Object o : list)
            System.out.print(o + " ");
        println("");
    }

    private static void println(final String msg) {
        System.out.println(msg);
        System.out.println();
    }
}