Index: src/java/org/apache/lucene/analysis/standard/READ_BEFORE_REGENERATING.txt
===================================================================
--- src/java/org/apache/lucene/analysis/standard/READ_BEFORE_REGENERATING.txt	(revision 0)
+++ src/java/org/apache/lucene/analysis/standard/READ_BEFORE_REGENERATING.txt	(revision 0)
@@ -0,0 +1,5 @@
+WARNING: if you change StandardTokenizerImpl.jflex and need to regenerate
+      the tokenizer, only use Java 1.5 or Java 1.6.
+      This grammar currently uses constructs (eg :digit:, :letter:) whose 
+      meaning can vary according to the JRE used to run jflex.  See
+      https://issues.apache.org/jira/browse/LUCENE-1126 for details.
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