Oracle released Java 7u1  on October 19. According to the release notes
and tests done by the Lucene committers, all bugs reported on July 28 are
fixed in this release, so code using Porter stemmer no longer crashes with
SIGSEGV. We were not able to experience any index corruption anymore, so it
is safe to use Java 7u1 with Lucene Core and Solr.
On the same day, Oracle released Java 6u29  fixing the same problems
occurring with Java 6, if the JVM switches -XX:+AggressiveOpts or
-XX:+OptimizeStringConcat were used. Of course, you should not use
experimental JVM options like -XX:+AggressiveOpts in production
environments! We recommend everybody to upgrade to this latest version 6u29.
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). For more information, read
JRE_VERSION_MIGRATION.txt in your distribution package!
On behalf of the Apache Lucene/Solr committers,