ArrayListSamples.java

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

public class ArrayListSamples {
    public static void main(String[] args) {
        ArrayList<String> a = new ArrayList<>();
        a.add("zero");
        a.add("one");
        a.add("two");
        a.add("three");
        a.add("four");
        a.add("five");

        assert a.size() == 6;

        List<String> sublist = a.subList(2, 5); 
        assert sublist.toString().equals("[two, three, four]");

        a.addAll(sublist);
        assert a.size() == 9;
        assert a.isEmpty() == false;

        assert a.contains("two") == true;
        assert a.contains("nine") == false;

        assert a.get(1) == "one";

        try { a.get(-1); } 
        catch (IndexOutOfBoundsException ex) { assert ex.getMessage().equals("-1"); }

        assert a.indexOf("two") == 2;
        assert a.lastIndexOf("two") == 6;
        assert a.indexOf("nine") == -1;

        // compile error > String[] array = a.toArray();
        // ArrayListSamples.java:12: error: incompatible types
        //         String[] array = a.toArray();
        //                            ^
        // required: String[]
        // found:    Object[]

        String[] array = a.toArray(new String[0]);
        log("\n" + Arrays.toString(array));

        // compile error > String s; for (s : a) {}
        // ArrayListSamples.java:24: error: not a statement
        //      for (s : a) {}
        //           ^

        logln("\nfor-each loop--->");
        for (String s : a) {
            log(" " + s + " ");
        }

        logln("\nlist iterator-->");
        ListIterator<String> lit = a.listIterator(1);
        while (lit.hasNext()) {
            log(" " + lit.next() + " ");
        }
        lit.add("six");
        assert a.size() == 10;

        logln("\niterator-->");
        Iterator<String> iit = a.iterator();
        while (iit.hasNext()) {
               log(" " + iit.next() + " ");
        }

        a.ensureCapacity(5);
        assert a.size() == 10;

        ArrayList<String> elems = new ArrayList<>();
        elems.add("two");
        elems.add("four");
        a.removeAll(elems);
        assert a.size() == 6;

        a.clear();
        assert a.size() == 0;
    }

    private static void logln(String s) {
        System.out.println(s);
    }

    private static void log(String s) {
        System.out.print(s);
    }   
}