[jira] [Commented] (TIKA-719) Concurrent usage of HtmlParser causes infinite loop in HashMap

["Jukka Zitting (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TIKA-719?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13108023#comment-13108023 ] 

Jukka Zitting commented on TIKA-719:
------------------------------------

Looks like a duplicate of TIKA-599.

> Concurrent usage of HtmlParser causes infinite loop in HashMap
> --------------------------------------------------------------
>
>                 Key: TIKA-719
>                 URL: https://issues.apache.org/jira/browse/TIKA-719
>             Project: Tika
>          Issue Type: Bug
>          Components: parser
>    Affects Versions: 0.9
>         Environment: SLES 10, JBoss 4.2
>            Reporter: Christian Goeller
>            Assignee: Ken Krugler
>
> When using Tika in a multithreaded environment I encounter sometimes 2 different types of problems with the HtmlParser
> 1. NullPointerException in HtmlParser
> java.lang.NullPointerException
> null
> org.ccil.cowan.tagsoup.Element.<init>(Element.java:39)
> org.ccil.cowan.tagsoup.Parser.setup(Parser.java:467)
> org.ccil.cowan.tagsoup.Parser.parse(Parser.java:439)
> org.apache.tika.parser.html.HtmlParser.parse(HtmlParser.java:198)
> org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:197)
> org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:197)
> org.apache.tika.parser.AutoDetectParser.parse(AutoDetectParser.java:135)
> org.apache.tika.parser.AutoDetectParser.parse(AutoDetectParser.java:148)
> 2. infinite loop in HashMap
> java.util.HashMap.get(HashMap.java:303)
> org.ccil.cowan.tagsoup.Schema.getElementType(Schema.java:122)
> org.ccil.cowan.tagsoup.Parser.gi(Parser.java:959)
> org.ccil.cowan.tagsoup.HTMLScanner.scan(HTMLScanner.java:505)
> org.ccil.cowan.tagsoup.Parser.parse(Parser.java:449)
> org.apache.tika.parser.html.HtmlParser.parse(HtmlParser.java:198)
> org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:197)
> org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:197)
> org.apache.tika.parser.AutoDetectParser.parse(AutoDetectParser.java:135)
> org.apache.tika.parser.AutoDetectParser.parse(AutoDetectParser.java:148)
> Having a closer look at the code of HtmlParser and several tagsoup classes I assume that the problems comes 
> from the concurrent usage of a HashMap.
> The class org.apache.tika.parser.html.HtmlParser has a static field HTML_SCHEMA.
> {code}
> /**
>  * HTML schema singleton used to amortize the heavy instantiation time.
>  */
> private static final Schema HTML_SCHEMA = new HTMLSchema();
> {code}
> The class HTMLSchema has a field elementTypes of type HashMap.
> {code}
> private HashMap theElementTypes = new HashMap();          // String -> ElementType
> {code}
> As the HtmlSchema is held static the HashMap is accessed concurrently.
> See here for a similar problem: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6423457
> Maybe the HTML_SCHEMA should not be static.
> Unfortunately the bug cannot be reproduced easily.

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