Java String Utility.

Trim space and null.

public static String trim(String str) {
        if (str != null && !str.isEmpty()) {
            String rs = str.trim();
            rs = rs.replaceAll("\\s+", " ");
            return rs;
        }
        return "";
    }

Check string is null or empty.

public static boolean isNulOrEmpty(String value) {
        return value == null || value.trim().isEmpty();
    }

Check string is positive number.

public static boolean isPositiveNumber(String value) {
        if (value != null) {
            value = value.replaceAll("\\s+", "");
            if (!value.isEmpty()) {
                if (value.matches("^[0-9]+$")) {
                    return isNumber(value) && (toBigDecimal(value).longValue() > 0L);
                }
            }
        }
        return true;
    }
    //---------------------
    Check Time (HH:MM): isValidWithPattern(tmpBis, "([0-9]|0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]");
    Check Time (HH:MM:SS): isValidWithPattern(tmpBis, "([0-9]|0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]");

Check validate email address with regular expression.

public static boolean isValidEmailAddress(String email) {
        if (email != null) {
            email = email.replaceAll("\\s+", "");
            if (!email.isEmpty()) {
                String ePattern = "^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\])|(([a-zA-Z\\-0-9]+\\.)+[a-zA-Z]{2,}))$";
                java.util.regex.Pattern p = java.util.regex.Pattern.compile(ePattern);
                java.util.regex.Matcher m = p.matcher(email);
                return m.matches();
            }
        }
        return true;
    }

Check validate string with regular expression.

public static boolean isValidWithPattern(String value, String pattern) {
        if (value != null) {
            if (!value.isEmpty()) {
                java.util.regex.Pattern p = java.util.regex.Pattern.compile(pattern);
                java.util.regex.Matcher m = p.matcher(value);
                return m.matches();
            }
        }
        return true;
    } 

--------------------

--------------------