java - How can a string accept an integer? -

can variable string accept integer value well. or can concat integer string ?

example:

public class teststring1 {         public static void main(string[] args) {         string str = "420";         str += 42;         system.out.print(str);     } } 

i expecting compilation error on here because string getting concatenated integer.

jls documentation on string concatination operator(+)-

15.18.1 string concatenation operator +

if 1 operand expression of type string, string conversion performed on other operand produce string @ run time. result reference string object (newly created, unless expression compile-time constant expression (§15.28))that concatenation of 2 operand strings. characters of left-hand operand precede characters of right-hand operand in newly created string. if operand of type string null, string "null" used instead of operand

that why string + int not produce error. , prints 42042