[Java] char to int / int to char / char to str / str to char array

public class test {
	public static void main(String[] args) {
		char c = '1';
		int a = c - '0';
		System.out.println(a);	// 1
		
		int b = 2;
		char ch = (char)(b + '0');
		System.out.println(ch);	// 2
		
		c = 'a';
		String s = Character.toString(c);
		s = new Character('a').toString();
		
		String str = "abc";
		char[] arr = str.toCharArray();
		
	}
}