code: public static String join(Iterable<?> iterable, CharSequence separator) {
  		return IteratorExtensions.join(iterable.iterator(), separator);
  	}
docs: Returns the concatenated string representation of the elements in the given iterable. The {@code separator} is
  used to between each pair of entries in the input. The string <code>null</code> is used for <code>null</code>
  entries in the input.
  
  @param iterable
  the iterable. May not be <code>null</code>.
  @param separator
  the separator. May not be <code>null</code>.
  @return the string representation of the iterable's elements. Never <code>null</code>.
  @see #join(Iterable, CharSequence, org.eclipse.xtext.xbase.lib.Functions.Function1)