src/share/classes/java/util/regex/Pattern.java

*** 482,492 ****
   *
   * <a name="groupname">
   * <h5> Group name </h5>
   * <p>A capturing group can also be assigned a "name", a <tt>named-capturing group</tt>,
   * and then be back-referenced later by the "name". Group names are composed of
!  * the following characters:
   *
   * <ul>
   *   <li> The uppercase letters <tt>'A'</tt> through <tt>'Z'</tt>
   *        (<tt>'&#92;u0041'</tt>&nbsp;through&nbsp;<tt>'&#92;u005a'</tt>),
   *   <li> The lowercase letters <tt>'a'</tt> through <tt>'z'</tt>
--- 482,492 ----
   *
   * <a name="groupname">
   * <h5> Group name </h5>
   * <p>A capturing group can also be assigned a "name", a <tt>named-capturing group</tt>,
   * and then be back-referenced later by the "name". Group names are composed of
!  * the following characters. The first character must be a <tt>letter</tt>.
   *
   * <ul>
   *   <li> The uppercase letters <tt>'A'</tt> through <tt>'Z'</tt>
   *        (<tt>'&#92;u0041'</tt>&nbsp;through&nbsp;<tt>'&#92;u005a'</tt>),
   *   <li> The lowercase letters <tt>'a'</tt> through <tt>'z'</tt>
*** 2565,2575 ****
                  head.next = expr(tail);
                  head = tail = new Ques(head, INDEPENDENT);
                  break;
              case '<':   // (?<xxx)  look behind
                  ch = read();
!                 if (ASCII.isLower(ch) || ASCII.isUpper(ch) || ASCII.isDigit(ch)) {
                      // named captured group
                      String name = groupname(ch);
                      if (namedGroups().containsKey(name))
                          throw error("Named capturing group <" + name
                                      + "> is already defined");
--- 2565,2575 ----
                  head.next = expr(tail);
                  head = tail = new Ques(head, INDEPENDENT);
                  break;
              case '<':   // (?<xxx)  look behind
                  ch = read();
!                 if (ASCII.isLower(ch) || ASCII.isUpper(ch)) {
                      // named captured group
                      String name = groupname(ch);
                      if (namedGroups().containsKey(name))
                          throw error("Named capturing group <" + name
                                      + "> is already defined");