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https://issues.apache.org/jira/browse/LUCENE-3349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13072493#comment-13072493
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Robert Muir commented on LUCENE-3349:
-------------------------------------
I would say maybe we should remove the advice about 'In case you upgrade to
java 7', instead recommending that you *do not use* java 7.
> Place warning about today's released Java7 version on Lucene/Solr/Root
> webpage's news and send mail to java-user
> ----------------------------------------------------------------------------------------------------------------
>
> Key: LUCENE-3349
> URL: https://issues.apache.org/jira/browse/LUCENE-3349
> Project: Lucene - Java
> Issue Type: Sub-task
> Components: general/test
> Environment: Java7
> Reporter: Uwe Schindler
> Assignee: Uwe Schindler
>
> Today, JDK/JRE 1.7.0 GA was released by Oracle. Unfortunately they didn't fix
> the Hotspot problems affecting loops to be miscompiled (LUCENE-3335,
> LUCENE-3346). This can lead to Solr crashing with default configuration on
> startup or sudden index corrumption depending on configuration.
> We should send an email to the java-user and solr-user list describing the
> problem. Also place a note in the news section of Solr, Lucene Core and
> top-level website.
> I propose the following text:
> {quote}
> *Jul 28th, 2011: WARNING: Index corruption and crashes in Apache Lucene Core
> / Apache Solr with Java 7*
> Oracle released *Java 7* today. Unfortunately it contains hotspot compiler
> optimizations, which miscompile some loops. This can affect code of several
> Apache projects. Sometimes JVMs only crash, but in several cases, results
> calculated can be incorrect, leading to bugs in applications (see Hotspot bug
> [http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7070134]).
> *Apache Lucene Core* and *Apache Solr* are two Apache projects, which are
> affected by these bugs, namely all versions released until today. Solr users
> with the default configuration will have Java crashing with SIGSEGV as soon
> as they start to index documents, as one affected part is the well-known
> Porter stemmer (see LUCENE-3335). Other loops in Lucene may be miscompiled,
> too, leading to index corruption (especially on Lucene trunk with pulsing
> codec; other loops may be affected, too - LUCENE-3346).
> These problems were detected only 5 days before the official Java 7 release,
> so Oracle had no time to fix those bugs, affecting also many more
> applications. In response to our questions, they proposed to include the
> fixes into service release u2 (eventually into service release u1, see
> [http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2011-July/005971.html]).
> This means you cannot use Apache Lucene/Solr with Java 7 releases before
> Update 2! If you do, please don't open bug reports, it is not the committers'
> fault! At least disable loop optimizations using the -XX:-UseLoopPredicate
> JVM options to not risk index corruptions.
> Please note: Also Java 6 users are affected, if they use one of those JVM
> options, which are *not* enabled by default: -XX:+OptimizeStringConcat or
> -XX:+AggressiveOpts
> It is strongly recommended not to use any hotspot optimization switches in
> any Java version without extensive testing!
> In case you upgrade to Java 7, remember that you may have to reindex, as the
> unicode version shipped with Java 7 changed and tokenization behaves
> differently (e.g. lowercasing)!
> {quote}
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