What are the original reasons for ToString() in Java and .NET?

Question

I\'ve used ToString() modestly in the past and I\'ve found it very useful in many circumstances. However, my usage of this method would hardly justify to put th

Answer 1

I can think of two technical reasons for defining toString() on java.lang.Object.

• The PrintStream.print(Object) API (for example) depends on Object.toString();

• The String concatenation operator + depends on Object.toString() in the case where one of the operands is a non-String reference type.

As an alternative, it would have been possible to define an interface (say) Printable that offered a toString()-like method and defined the above to require a Printable. (And that would avoid the puzzlement that arises when a newbie tries to print an object that doesn't overload toString()).

However, it is really convenient that print (etc) and + concatenation just work for everything. And I'm sure that's why Java was designed that way.

EDIT - in response to this followup question from the OP:

Static hypothetical FromString vs Serialization: sure, but that's quite a different story, right?

Assuming that I am parsing your syntax correctly ...

The goal of Object serialization is to provide a flat representation that can be reliably and efficiently deserialized. The goal of toString() is to provide a textual representation that is easy to read. In practice, "easy to read" and "reliably and efficiently deserializable" are contradictory.