The base class Object has a method toString that subclasses redefine
to print out a representation of
the object. If x is any object, then
x.toString()
converts it to a string.
If x is a number, then you can't call x. toString (), because numbers
aren't objects in Java, and you can't
apply methods. Instead, you are supposed to use
String.valueOf(x)
Tip
Just concatenate with an empty string:
"" + x
This converts x to a string. If x is a number, then its value is turned
into a string. If x is an object, then its toString method is invoked.
There is no penalty. The Java compiler is aware of this idiom, and it
does not generate code to concatenate an empty string.
