code: public static final boolean isValid(final String value) {
          if (value == null) {
              return true;
          }
          if (value.length() != 36) {
              return false;
          }
          try {
              UUID.fromString(value);
              return true;
          } catch (final RuntimeException ex) {
              return false;
          }
      }
docs: Check that a given string is a valid {@link java.util.UUID}.
  
  @param value
  Value to check.
  
  @return Returns <code>true</code> if it's a valid UUIDd else <code>false</code> is returned.