Java Utililty Methods Vector Difference

Vector r = new Vector();
for (int i = 0; i < a.size(); i++) {
    boolean inB = false;
    for (int j = 0; j < b.size(); j++) {
        if (a.elementAt(i).equals(b.elementAt(j))) {
            inB = true;
            break;
    if (!inB)
        r.add(a.elementAt(i));
return r;

This method returns a Vector containing the set of objects contained in vectA that are not contained in vectB.

This method will always return a new, non-null Vector, even if vectA and/or vectB are null.

Vector result = new Vector();
Object item;
if (vectA == null) {
    return result;
if (vectB == null) {
    return (Vector) vectA.clone();
if (vectA.size() + vectB.size() > 10) 
    Hashtable workSetB = new Hashtable();
    Enumeration Enum;
    Enum = vectB.elements();
    while (Enum.hasMoreElements()) {
        item = Enum.nextElement();
        workSetB.put(item, item);
    Enum = vectA.elements();
    while (Enum.hasMoreElements()) {
        item = Enum.nextElement();
        if (!workSetB.containsKey(item)) {
            result.addElement(item);
} else {
    for (int i = 0; i < vectA.size(); i++) {
        item = vectA.elementAt(i);
        if (!vectB.contains(item)) {
            result.addElement(item);
return result;

This method returns a Vector containing the elements of vectA minus the elements of vectB.

Hashtable workSetB = new Hashtable();
Vector result = new Vector();
Enumeration Enum;
Object item;
if (vectA == null) {
    return result;
result = (Vector) vectA.clone();
...