1.
public static boolean isBlank(final CharSequence cs) { int strLen; if (cs == null || (strLen = cs.length()) == 0) { return true; } for (int i = 0; i < strLen; i++) { if (!Character.isWhitespace(cs.charAt(i))) { return false; } } return true; } public static boolean isNotBlank(final CharSequence cs) { return !isBlank(cs); } public static String defaultString(Object obj) { return obj == null ? "" : obj.toString(); } }