Comments on: NullPointerExceptions Are Not Helpful http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/ Robert Fischer and Brian Hurt on Punditry, Programming Languages, and Other Religious Issues Mon, 08 Sep 2008 07:49:16 +0000 http://wordpress.org/?v=2.6.1 By: My Frustrations with REXML: Ruby’s Standard Library for Reading/Writing XML; or, Ruby’s Problem Is Its Type System, and Don’t Try to Tell Me Otherwise | Enfranchised Mind http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-33698 My Frustrations with REXML: Ruby’s Standard Library for Reading/Writing XML; or, Ruby’s Problem Is Its Type System, and Don’t Try to Tell Me Otherwise | Enfranchised Mind Thu, 21 Aug 2008 18:41:49 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-33698 [...] BEEN FIXED WITH STATIC TYPING. Even more if you have a type system which can check nulls for you. Null pointers/”nil when you didn’t expect it!” errors are totally solvable problems. The fact [...] [...] BEEN FIXED WITH STATIC TYPING. Even more if you have a type system which can check nulls for you. Null pointers/”nil when you didn’t expect it!” errors are totally solvable problems. The fact [...]

]]> By: Upped The Recent Post/Popular Post Widget Count | Enfranchised Mind http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-33668 Upped The Recent Post/Popular Post Widget Count | Enfranchised Mind Tue, 12 Aug 2008 19:33:24 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-33668 [...] NullPointerExceptions Are Not Helpful [...] [...] NullPointerExceptions Are Not Helpful [...]

]]> By: Enfranchised Mind » 7 Actually Useful Things You Didn’t Know Static Typing Could Do: An Introduction for the Dynamic Language Enthusiast http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-33001 Enfranchised Mind » 7 Actually Useful Things You Didn’t Know Static Typing Could Do: An Introduction for the Dynamic Language Enthusiast Mon, 14 Apr 2008 14:50:57 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-33001 [...] right. If you switch to Ocaml, the compiler will guaranty that you never see a $!# NullPointerException (or equivalent) again. Ever. [...] [...] right. If you switch to Ocaml, the compiler will guaranty that you never see a $!# NullPointerException (or equivalent) again. Ever. [...]

]]> By: Brian http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-32911 Brian Sat, 29 Mar 2008 16:55:30 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-32911 Also note that @nullable and @notnull are <EM>type annotations</EM>, in the sense of Ocaml or Haskell types (Ocaml calls nullable values "options", Haskell "maybes"- same idea). Which means that not only should this capability (among others) be expressed in the type system, the compiler should be able to deduce whether or not a particular value is nullable or not automatically- the annotation should be optional. Again, Haskell, Ocaml, et. al. do precisely this this. Also note that @nullable and @notnull are type annotations, in the sense of Ocaml or Haskell types (Ocaml calls nullable values “options”, Haskell “maybes”- same idea).

Which means that not only should this capability (among others) be expressed in the type system, the compiler should be able to deduce whether or not a particular value is nullable or not automatically- the annotation should be optional. Again, Haskell, Ocaml, et. al. do precisely this this.

]]> By: Robert Fischer http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-32900 Robert Fischer Thu, 27 Mar 2008 18:10:47 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-32900 In this case, the NPE was coming out of Hibernate. My IDE will not fix that. In this case, the NPE was coming out of Hibernate. My IDE will not fix that.

]]> By: Marc http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-32899 Marc Thu, 27 Mar 2008 17:53:39 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-32899 I like JetBrains' solution to the problem: http://www.jetbrains.com/idea/documentation/howto.html There's no reason to ever get an NPE if you're using that. I like JetBrains’ solution to the problem:

http://www.jetbrains.com/idea/documentation/howto.html

There’s no reason to ever get an NPE if you’re using that.

]]> By: Enfranchised Mind » My Frustrations with REXML: Ruby’s Standard Library for Reading/Writing XML; or, Ruby’s Problem Is Its Type System, and Don’t Try to Tell Me Otherwise http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-32872 Enfranchised Mind » My Frustrations with REXML: Ruby’s Standard Library for Reading/Writing XML; or, Ruby’s Problem Is Its Type System, and Don’t Try to Tell Me Otherwise Mon, 24 Mar 2008 21:59:56 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-32872 [...] BEEN FiXED WITH STATIC TYPING. Even more if you have a type system which can check nulls for you. Null pointers/”nil when you didn’t expect it!” errors are totally solvable problems. The fact [...] [...] BEEN FiXED WITH STATIC TYPING. Even more if you have a type system which can check nulls for you. Null pointers/”nil when you didn’t expect it!” errors are totally solvable problems. The fact [...]

]]> By: Enfranchised Mind » Some final Patterns http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-32074 Enfranchised Mind » Some final Patterns Sun, 16 Dec 2007 18:26:06 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-32074 [...] This code is pretty common: T out = null; if(someTest(in)) { out = value1; } else if(someOtherTest(in)) { out = value2; } else { out = value3; } doSomethingWith(out) If you change T out = null; to just final T out;, the compiler will check that all code paths leading to “doSomethingWith(out)” will lead to “out” being assigned. And you can wipe out one more null in your code, which means one fewer opportunity for a NullPointerException to sneak out of your library and piss me off. [...] [...] This code is pretty common: T out = null; if(someTest(in)) { out = value1; } else if(someOtherTest(in)) { out = value2; } else { out = value3; } doSomethingWith(out) If you change T out = null; to just final T out;, the compiler will check that all code paths leading to “doSomethingWith(out)” will lead to “out” being assigned. And you can wipe out one more null in your code, which means one fewer opportunity for a NullPointerException to sneak out of your library and piss me off. [...]

]]> By: scott http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-31132 scott Mon, 25 Jun 2007 04:21:28 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-31132 I think that's Las Vegas debugging, technically ;) I think that’s Las Vegas debugging, technically ;)

]]> By: Robert http://enfranchisedmind.com/blog/2007/06/13/nullpointerexceptions-are-not-helpful/#comment-31111 Robert Mon, 18 Jun 2007 17:12:58 +0000 http://enfranchisedmind.com/blog/archive/2007/06/13/255#comment-31111 Blargh. <code>ParserContext</code> is an undocumented interface, whose implementation is being passed in. This is where abstraction ceases to be fun. Blargh.

ParserContext is an undocumented interface, whose implementation is being passed in.

This is where abstraction ceases to be fun.

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