public class ListOfStrings {
public static final int DEFAULT_CAPACITY = 4;
private String[] names;
private int size = 0;

public ListOfStrings() {
    this(DEFAULT_CAPACITY);
}

public ListOfStrings(int initialCapacity) {
    names = new String[initialCapacity];
}

public int getCapacity() {
    return names.length;
}

public int getSize() {
    return size;
}

// Adds name to the end of the list
public void add(String name) {
    if (this.getSize() == this.getCapacity()) {
        // Double the size of the array
        String[] temp = new String[this.getCapacity() * 2];
        System.arraycopy(names, 0, temp, 0, this.getCapacity());
        names = temp;
    }

    names[size] = name;
    size++;
}

// set item i to the given name
public void set(int i, String name) {
    if (i < 0 || i > this.getSize() - 1) {
        // we have a problem
        String message = "index " + i + " not valid";
        throw new IndexOutOfBoundsException(message);
    }

    names[i] = name;
}

// returns the item at index i
public String get(int i) {
    if (i < 0 || i > this.getSize() - 1) {
        // we have a problem
        String message = "index " + i + " not valid";
        throw new IndexOutOfBoundsException(message);
    }

    return names[i];
}

// removes and returns item i from the list
public String remove(int i) {//
    if (i < 0 || i > this.getSize() - 1) {
        // we have a problem
        String message = "index " + i + " not valid";
        throw new IndexOutOfBoundsException(message);
    }

    String removedItem = this.get(i); // save item to return

    // now adjust the array
    if (i < size - 1) {
        System.arraycopy(names, i + 1, names, i, size - i - 1);
    }
    size--;

    return removedItem;
}

@Override
public String toString() {
    String s = "";
    s += "[";
    boolean first = true;
    for (int i = 0; i < size; i++) {
        if (first) {
            s += names[i];
            first = false;
        } else {
            s += ", ";
            s += names[i];
        }
    }
    s += "]";

    return s;
}

/*
 * Removes and returns the first string in the list. If the list is empty,
 * null is returned.
 */
public String removeFirst() {
    if (size < 1)
        return null;
    String removeItem = this.get(0);

    this.remove(0);
    return removeItem;
}

/*
 * Removes and returns the last string in the list. If the list is empty,
 * null is returned.
 */
public String removeLast() {
    if (size < 1)
        return null;
    String removeItem = this.get(size - 1);
    this.remove(size - 1);
    size--;

    return removeItem;
}

/*
 * Removes all unused array elements from the end of the arry, if any exit.
 * After calling this method the size and the capacity of the list should be
 * same.
 */
public void compress() {
    if (size == DEFAULT_CAPACITY)
        return;
    if (size == 0) {
        this.names = new String[] {};
        return;
    }

    String[] newList = new String[size];
    System.arraycopy(names, 0, newList, 0, size);
    this.names = newList;

}

/*
 * Increases the capacity, if needed, to new specified capacity. This may
 * mean making a new, lager array.
 */
public void ensureCapacity(int newCapacity) {

    if (newCapacity <this.getCapacity()) {

        String message = "The new capacity must be lager than the original capacity("
                + this.getCapacity() + ").";
        throw new IndexOutOfBoundsException(message);

    }

    String[] newList = new String[newCapacity];

    if (size > 0)
        System.arraycopy(names, 0, newList, 0, size);

    this.names = newList;

}

/*
 * Returns the index of the first occurrence of specified string. If the
 * string is not in the list, returns -1.
 */
public int getIndex(String s) {
    if (size == 0) {
        return -1;

    }
    for (int i = 0; i < size; i++) {
        if (get(i).equals(s)) {
            return i;
        }
    }
    return -1;
}

/*
 * Removes and returns the first occurrence of the specified string. If the
 * String is not in the list, returns null;
 */
public String remove(String s) {

    for (int i = 0; i < size; i++) {
        if (get(i).equals(s)) {
            this.remove(i);
            return s;
        }
    }
    return null;
}

/* Removes all strings from the list and set the capacity to the default capacity.
 *
 * */
public void Clear() {
    names = new String[DEFAULT_CAPACITY];
    size = 0;
    }
}

@Override
public String toString() {
    if (size < 1)
        return "[]";
    StringBuilder readable = new StringBuilder(size * 7);
    String intro = "[";
    for (int i = 0; i < size; i++) { // T item: names
        readable.append(intro).append(names[i]);
        intro = ", ";
    }
    return readable.append(']').toString();
}