Java String Utility Methods

1. Capitalize the first letter

	// capitalize first letter
	public static String toUpperCaseFirstOne(String s) {
		if (Character.isUpperCase(s.charAt(0))) {
			return s;
		} else {
			return (new StringBuilder()).append(Character.toUpperCase(s.charAt(0))).append(s.substring(1)).toString();
		}
	}

	// capitalize first letter
	public static String upperCaseFirstOne1(String str) {
		return str.substring(0, 1).toUpperCase() + str.substring(1);
	}

	// capitalize first letter
	public static String upperCaseFirstOne2(String str) {
		char[] ch = str.toCharArray();
		if (ch[0] >= 'a' && ch[0] <= 'z') {
			ch[0] = (char) (ch[0] - 32);
		}
		return new String(ch);
	}

 

2. The first letter is lowercase

	// Convert the first letter to lowercase
	public static String toLowerCaseFirstOne(String s) {
		if (Character.isLowerCase(s.charAt(0))) {
			return s;
		} else {
			return (new StringBuilder()).append(Character.toLowerCase(s.charAt(0))).append(s.substring(1)).toString();
		}
	}