int a char
char c = Character.forDigit(Integer, 10);
// OR
char c = (char) (Integer + '0');
Ejemplo:
Character.forDigit(8, 10);
>>>
'8'
int a char[]
Ejemplo:
int n = 123;
String str = String.valueOf(n);
char[] array = str.toCharArray();
char a int
int n = charNumber - '0';
char[] a int
Ejemplo:
char[] array = new char[]{
'1', '2', '3'};
String str = String.valueOf(array);
int n = Integer.valueOf(str);