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Groups > comp.lang.java.programmer > #33778

Re: Java Checked Exception is BAD!

From Sebastian <news@seyweiler.dyndns.org>
Newsgroups comp.lang.java.programmer
Subject Re: Java Checked Exception is BAD!
Date 2016-02-11 20:32 +0100
Organization albasani.net
Message-ID <n9inkv$a0o$1@news.albasani.net> (permalink)
References (9 earlier) <83011e99-7f61-4f02-8cba-2f2c9107d8ee@googlegroups.com> <fda72a96-d611-4be9-a2db-c3123f62cdee@googlegroups.com> <56bcaad1$0$23816$e4fe514c@news.xs4all.nl> <n9iei6$sbr$1@dont-email.me> <56bccc91$0$23792$e4fe514c@news.xs4all.nl>

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Am 11.02.2016 19:01, schrieb Silvio:

[snip]

> Right, so the context in which a lambda is used determines what checked
> exceptions it can throw

[snip]

> I was not at all limiting this to streams. They are great but there are
> much more places where lambdas can be used to create abstractions.

[snip]

> I realize that lambdas did not exist when checked exceptions where put
> into the language. And I also agree that it is not at all black or
> white. Checked exceptions have advantages as well as disadvantages. What
> weighs stronger is partly a matter of taste. But the way they limit
> lambdas most definitely weighs against them.

I think that is true, to some extent, but not to a very large extent. On 
the one hand, when you take a pure view of lambdas as functions, they 
have no business throwing exceptions in the first place, checked or 
unchecked. That is mostly taken the view by the Streams API. The Stream 
API provides some means that can function as an alternative for 
exceptions, such as Optional (and there are libraries that provide for 
more possibilities).

I don't find this view too limiting. Indeed, I sympathize with it. This 
is partly also because of the difficulties that are raised by exceptions 
(checked or unchecked) in parallel processing which have been discussed 
in this thread and been demonstrated by Eric.

CompletableFuture takes another view (lambdas may be used to provide 
tasks, which definitely aren't functions), and at the same time also 
provides means to deal with exceptions (CompletionException and the 
various flavors of exceptionally/whenComplete/handle). These means are a 
bit clumsy sometimes, but some additional utilities to address the weak 
points will be in Java 9.

That leaves the cases Silvio mentions where the compiler wants to 
enforce exception handling because it's not smart enough, as in the 
example I posted earlier in this topic. These definitely are painful, 
and they very much underline the fact that a library author should not 
hastily impose his view on what exceptions his clients should be 
required to handle on said clients. Libraries may come to be used in 
unexpected contexts, while clairvoyance remains as difficult as always.

These cases are mostly in legacy libararies, some of them in the JDK 
itself. I am in agrrement with Brian Goetz (can't find the reference at 
the moment, sorry, but it was somewhere in the Expert Group discussions 
for Project Lambda) in expecting that library code will evolve to throw 
fewer checked exceptions, and at the same time not believing they should 
be thrown completely out of application code.

I regret that the tone in this part of the conversation has started to 
veer back towards the acrimonious. Please try to stay civil, guys.

-- Sebastian

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Thread

Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 07:18 -0800
  Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-04 08:15 -0800
    Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-04 17:57 +0100
      Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-04 10:09 -0800
        Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-04 21:01 +0100
          Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-04 12:14 -0800
          Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-04 15:16 -0500
            Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-04 21:37 +0100
              Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-04 13:08 -0800
                Re: Java Checked Exception is BAD! 4ndre4 <4ndre4@4ndre4.com.invalid> - 2016-02-04 21:16 +0000
                Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-04 13:28 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-04 23:11 +0000
                Re: Java Checked Exception is BAD! a.laforgia@gmail.com - 2016-02-05 04:21 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-05 13:07 +0000
              Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-04 18:04 -0500
                Re: Java Checked Exception is BAD! Gene Wirchenko <genew@telus.net> - 2016-02-05 11:40 -0800
          Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-04 23:22 +0100
          Re: Java Checked Exception is BAD! ruben <ceo@iran.gov> - 2016-02-15 11:45 +0000
      Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 11:57 -0800
        Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-04 21:07 +0100
    Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 11:10 -0800
      Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-04 11:28 -0800
        Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 11:33 -0800
          Re: Java Checked Exception is BAD! 4ndre4 <4ndre4@4ndre4.com.invalid> - 2016-02-04 21:08 +0000
          Re: Java Checked Exception is BAD! Lew <lewbloch@gmail.com> - 2016-02-04 16:09 -0800
  Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-04 12:00 -0500
  Re: Java Checked Exception is BAD! Marcel Mueller <news.5.maazl@spamgourmet.org> - 2016-02-04 19:28 +0100
    Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 11:15 -0800
      Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-04 14:51 -0500
  Re: Java Checked Exception is BAD! 4ndre4 <4ndre4@4ndre4.com.invalid> - 2016-02-04 21:07 +0000
    Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 14:36 -0800
      Re: Java Checked Exception is BAD! a.laforgia@gmail.com - 2016-02-05 05:28 -0800
  Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 15:31 -0800
    Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-05 08:20 -0500
      Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-05 08:25 -0800
        Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-05 08:47 -0800
          Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-05 16:09 -0800
            Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-06 08:38 -0500
              Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-06 14:13 +0000
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-06 15:23 +0100
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-07 14:49 +0100
                Re: Java Checked Exceptions Robert Klemme <shortcutter@googlemail.com> - 2016-02-07 21:55 +0100
                Re: Java Checked Exceptions boxzou@gmail.com - 2016-02-07 14:39 -0800
                Re: Java Checked Exceptions Robert Klemme <shortcutter@googlemail.com> - 2016-02-08 13:30 +0100
                Re: Java Checked Exceptions boxzou@gmail.com - 2016-02-08 06:14 -0800
                Re: Java Checked Exceptions Robert Klemme <shortcutter@googlemail.com> - 2016-02-08 20:55 +0100
                Re: Java Checked Exceptions Lew <lewbloch@gmail.com> - 2016-02-08 16:06 -0800
                Re: Java Checked Exceptions boxzou@gmail.com - 2016-02-08 18:38 -0800
                Re: Java Checked Exceptions Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-09 12:15 +0000
                Re: Java Checked Exceptions boxzou@gmail.com - 2016-02-09 04:59 -0800
                Re: Java Checked Exceptions Lew <lewbloch@gmail.com> - 2016-02-10 12:13 -0800
                Re: Java Checked Exceptions boxzou@gmail.com - 2016-02-10 19:00 -0800
                Re: Java Checked Exceptions Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-11 12:18 +0000
                Re: Java Checked Exceptions leif.roar@dimnakorr.com - 2016-02-11 04:43 -0600
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 14:34 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 14:11 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-07 23:19 +0000
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 15:42 -0800
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-06 09:43 -0500
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 14:14 -0800
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-08 09:22 -0500
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 11:01 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 11:08 -0800
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-08 22:02 +0100
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 14:09 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-07 23:29 +0000
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-08 21:49 +0100
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-08 17:23 -0500
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 18:46 -0800
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-09 08:21 +0100
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-09 04:58 -0800
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-09 08:17 -0500
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-09 07:57 -0800
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-10 02:37 +0100
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-10 18:58 -0800
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-11 08:13 -0500
                Re: Java Checked Exception is BAD! Lew <lewbloch@gmail.com> - 2016-02-11 14:02 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-11 16:41 -0800
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-10 02:31 +0100
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-10 18:47 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-09 12:26 +0000
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-09 04:57 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-09 18:27 +0000
              Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 20:19 -0800
            Re: Java Checked Exception is BAD! Robert Klemme <shortcutter@googlemail.com> - 2016-02-06 16:01 +0100
              Re: Java Checked Exception is BAD! 4ndre4 <4ndre4@4ndre4.com.invalid> - 2016-02-06 15:10 +0000
                Re: Java Checked Exception is BAD! Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2016-02-06 17:59 -0800
                Re: Java Checked Exception is BAD! 4ndre4 <4ndre4@4ndre4.com.invalid> - 2016-02-07 09:34 +0000
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 14:23 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 20:52 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 21:13 -0800
              Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-07 14:19 -0800
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-07 23:42 +0000
                Re: Java Checked Exception is BAD! Robert Klemme <shortcutter@googlemail.com> - 2016-02-08 13:17 +0100
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 04:39 -0800
                Re: Java Checked Exception is BAD! Lew <lewbloch@gmail.com> - 2016-02-08 16:05 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 18:35 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 19:10 -0800
                Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-08 19:12 -0800
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-11 16:37 +0100
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-11 12:00 -0500
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-11 19:01 +0100
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-11 20:32 +0100
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-11 15:20 -0500
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-11 23:53 +0100
                Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-11 18:21 -0500
                Re: Java Checked Exception is BAD! Lew <lewbloch@gmail.com> - 2016-02-11 15:45 -0800
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-12 01:19 +0100
                Re: Java Checked Exception is BAD! Lew <lewbloch@gmail.com> - 2016-02-11 19:18 -0800
                Re: Java Checked Exception is BAD! Sebastian <news@seyweiler.dyndns.org> - 2016-02-12 08:31 +0100
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-12 15:33 +0100
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-12 15:41 +0100
                Re: Java Checked Exception is BAD! Silvio <silvio@internet.com> - 2016-02-12 15:42 +0100
                Re: Java Checked Exception is BAD! Martin Gregorie <martin@address-in-sig.invalid> - 2016-02-08 21:19 +0000
        Re: Java Checked Exception is BAD! Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-02-05 13:00 -0500
  Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 15:51 -0800
    Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 15:59 -0800
      Re: Java Checked Exception is BAD! boxzou@gmail.com - 2016-02-04 16:03 -0800
    Re: Java Checked Exception is BAD! Eric Douglas <e.d.programmer@gmail.com> - 2016-02-05 05:33 -0800
  Re: Java Checked Exception is BAD! Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2016-02-04 21:05 -0800
  Re: Java Checked Exception is BAD! ynseo <yeori.seo@gmail.com> - 2016-02-08 01:05 -0800
  Re: Java Checked Exception is BAD! Sebastian <sebastian.millies@softwareag.com> - 2016-02-19 03:43 -0800

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