Difference between Java's Vector.add() and Vector.addElement()?

Question

Please explain the difference between the Vector.add() method and the Vector.addElement() method, along with a sample code snippet

Answer 1

add() comes from the List interface, which is part of the Java Collections Framework added in Java 1.2. Vector predates that and was retrofitted with it. The specific differences are:

1. addElement() is synchronized. add() isn't. In the Java Collections Framework, if you want these methods to be synchronized wrap the collection in Collections.synchronizedList(); and

2. add() returns a boolean for success. addElement() has a void return type.

The synchronized difference technically isn't part of the API. It's an implementation detail.

Favour the use of the List methods. Like I said, if you want a synchronized List do:

List<String> list = Collections.synchronizedList(new ArrayList<String>());
list.add("hello");

Answer 2

The method signature is different, add returns true, while addElement is void.

from http://www.docjar.com/html/api/java/util/Vector.java.html

  153       public synchronized boolean add(E object) {
  154           if (elementCount == elementData.length) {
  155               growByOne();
  156           }
  157           elementData[elementCount++] = object;
  158           modCount++;
  159           return true;
  160       }

and

223       public synchronized void addElement(E object) {
  224           if (elementCount == elementData.length) {
  225               growByOne();
  226           }
  227           elementData[elementCount++] = object;
  228           modCount++;
  229       }