private boolean shouldBeEscaped(char c){
  return c < ' ' || (c >= '\u0080' && c < '\u00a0') || (c >= '\u2000' && c < '\u2100');
}

private boolean shouldBeEscaped ( char c ) { return c < ' ' || ( c >= '' && c < ' ' ) || ( c >= ' ' && c < '℀' ) ; }
json . org spec says that all control characters must be escaped .
