char  ca = str.toCharArray();
//Some manipulations on char  ...
String str2 = ca.toString();
System.out.println("String is " +str2);
Why can't we use toString() to convert char  to String?
There is no special Class called
char, Array's are native objects and their type really depend on what data type you used while using it.
Hence ovveriding it's toString() method is highly difficult to give you something in string format back.
Consider a case where you using an array like
int, what should
toString() give back ?
Hence the authors leave it as it gives you the default behaviour of Object class.