boolean (@NotNull Document document, final int line) { final CharSequence chars = document.getCharsSequence(); int start = document.getLineStartOffset(line); int end = Math.min(document.getLineEndOffset(line), document.getTextLength() - 1); for (int i = start; i <= end; i++) { if (!Character.isWhitespace(chars.charAt(i))) return false; } return true; }