It seems strange to have the methods
Character.isJavaIdentifierStart
and
Character.isJavaIdentifierPart
and yet there is no method
String.isJavaIdentifier

which would look something like this

    public boolean isJavaIdentifier() {
      int n = length();
      if (n==0) return false;
      if (!Character.isJavaIdentifierStart(charAt(0)))
          return false;
      for (int i = 1; i < n; i++)
          if (!Character.isJavaIdentifierPart(charAt(i)))
              return false;
      return true;
    }