code: public synchronized boolean removeElement(Object obj) {
          modCount++;
          int i = indexOf(obj);
          if (i >= 0) {
              removeElementAt(i);
              return true;
          }
          return false;
      }
docs: Removes the first (lowest-indexed) occurrence of the argument
  from this vector. If the object is found in this vector, each
  component in the vector with an index greater or equal to the
  object's index is shifted downward to have an index one smaller
  than the value it had previously.
  
  <p>This method is identical in functionality to the
  {@link #remove(Object)} method (which is part of the
  {@link List} interface).
  
  @param   obj   the component to be removed
  @return  {@code true} if the argument was a component of this
  vector; {@code false} otherwise.