Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Eric Sosman Newsgroups: comp.lang.java.programmer Subject: Re: how actually string store in java machine Date: Thu, 27 Mar 2014 08:54:36 -0400 Organization: A noiseless patient Spider Lines: 36 Message-ID: References: <8f7d9272-4b25-44c9-8c31-93ea754be4cb@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Thu, 27 Mar 2014 12:54:39 +0000 (UTC) Injection-Info: mx05.eternal-september.org; posting-host="bd4e1cba8d8592bec5d5ed9e4537fbfd"; logging-data="23193"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/FEb/TahsSlQE+Dtyu6pGD" User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 In-Reply-To: Cancel-Lock: sha1:3BQB4zVNfQx2k9/yoEniMMd275w= Xref: csiph.com comp.lang.java.programmer:27886 On 3/26/2014 7:37 PM, markspace wrote: > On 3/26/2014 10:54 AM, Eric Sosman wrote: > >> ... prints >> >> Foo.HELLO == "Hello": true >> >> ... on my Java 1.7.0_51 system. You might also want to re-read >> Section 3.10.5 of the Java Language Specification; for Java 7 and 8 >> it reads (in part) > > > Well, that I did not expect. No wonder it takes so long to load a class > if each class has to be parsed for string literals and each one added to > a hash map someplace. There's surely no parsing to speak of. The string literals' data arrives in the class' constant pool, along with a lot of other stuff, and is pretty easily located therein. I suspect that the time required to fish them out and intern() them is peanuts compared to the time spent on the rest of class loading and initialization (but I have absolutely no data to support my suspicion). And then there's the JIT ... > Grrr, I'm actually mad about that. String are *required* to be > intern'd?! That's really funky. I think so, too. It feels like an implementation detail that might better have been left unspecified. Similarly, I feel that the span of pooled Integer and suchlike objects ought not to be part of the language definition, but should have been left to the discretion of a JVM's implementors. -- Eric Sosman esosman@comcast-dot-net.invalid