code: @Pure
  	public static <T> String join(char leftSeparator, char rightSeparator, @SuppressWarnings("unchecked") T... strs) {
  		final StringBuilder buffer = new StringBuilder();
  		for (final Object s : strs) {
  			buffer.append(leftSeparator);
  			if (s != null) {
  				buffer.append(s.toString());
  			}
  			buffer.append(rightSeparator);
  		}
  		return buffer.toString();
  	}
docs: Merge the given strings with to separators.
  The separators are used to delimit the groups
  of characters.
  
  <p>Examples:
  <ul>
  <li><code>merge('{','}',"a","b","cd")</code> returns the string
  <code>"{a}{b}{cd}"</code></li>
  <li><code>merge('{','}',"a{bcd")</code> returns the string
  <code>"{a{bcd}"</code></li>
  </ul>
  
  @param <T> is the type of the parameters.
  @param leftSeparator is the left separator to use.
  @param rightSeparator is the right separator to use.
  @param strs is the array of strings.
  @return the string with merged strings.
  @since 4.0