OutOfMemoryError should not be wrapped in an IllegalStateException, as it is misleading for fault-tolerant programs [LUCENE-2511]

I have a program, which does explicit commits. On one occasion, I saw the following exception thrown:

java.lang.IllegalStateException: this writer hit an OutOfMemoryError; cannot commit
at org.apache.lucene.index.IndexWriter.prepareCommit(IndexWriter.java:4061)
at org.apache.lucene.index.IndexWriter.commit(IndexWriter.java:4136)
at org.apache.lucene.index.IndexWriter.commit(IndexWriter.java:4114)

In our program, we treat all errors as fatal and terminate the program (and restart). Runtime exceptions are sometimes handled differently, since they are usually indicative of a programming bug that might be recoverable. in some situations.

I think the OutOfMemoryError should not be wrapped as a runtime exception.. as this can mask a serious issue from a fault-tolerant application.

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Migrated from [LUCENE-2511](https://issues.apache.org/jira/browse/LUCENE-2511) by David Sitsky, updated Nov 30 2013

Start in org/apache/lucene/index/IndexWriter.java at prepareCommit and the commit call paths shown in the report. Trace how an OutOfMemoryError becomes an IllegalStateException, then inspect the surrounding tests if available. Done means the original OutOfMemoryError is not misleadingly wrapped during commit.

Written by the indexing model from the issue text.