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Re: If java doesn't support operator overloading, how does String + concatenation work

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On 4/30/2015 10:10 AM, Ajay Paul wrote:
> I understand that java doesn't support operator overloading. If so, how does String + concatenation work ?

     Java *does* support operator overloading.  You've noted that `+' can
concatenate two Strings; it can also add two doubles, or two floats, or
two longs, or two ints.  Similarly, `<' can compare doubles, floats,
longs, ints, shorts, chars, or bytes.  `==' and `!=' can compare all
those, and can compare references also.

     However, Java does not support programmer-defined overloads: Its
operators and their overloads are built in to the language, and cannot
be extended by writing Java code.  (In a trivial sense, defining a new
class or interface extends the `==' and `!=' and `?:' operators to
apply to new reference types -- but that's a pretty weak "overload.")

     A useful way to think about this is to separate the notion of an
operator from the particular source symbol that represents it.  We
may then say that the source symbol `+' can represent any of five
different operators, depending on context:

	String concatenation
	double addition
	float addition
	long addition
	int addition

(Note that although `+' can be used with short and char and byte as
well, these types are widened to int before the operator operates,
so there's really no "short addition" operator.)

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM

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If java doesn't support operator overloading, how does String + concatenation work Ajay Paul <ajaykpaul@gmail.com> - 2015-04-30 07:10 -0700
  Re: If java doesn't support operator overloading, how does String + concatenation work Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-04-30 11:32 -0400
    Re: If java doesn't support operator overloading, how does String   + concatenation work Robert Klemme <shortcutter@googlemail.com> - 2015-04-30 23:46 +0200
  Re: If java doesn't support operator overloading, how does String + concatenation work v_borchert@despammed.com (Volker Borchert) - 2015-05-01 06:33 +0000

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