Array & Set Example: Character vowel[] = { 'a', 'A', 'e', 'E', 'i', 'I', 'o', 'O', 'u', 'U' }; Set<Character> v = new HashSet<>(Arrays.asList(vowel)); StringBuilder & String Example: StringBuffer sb = new StringBuffer(); String str = sb.toString();
Conversion between String and Integer in java
From String to Integer Integer.parseInt(my_string); From Integer to String Integer.toString(my_integer);