13bedc087SDawid Weiss<!-- 23bedc087SDawid Weiss Licensed to the Apache Software Foundation (ASF) under one or more 33bedc087SDawid Weiss contributor license agreements. See the NOTICE file distributed with 43bedc087SDawid Weiss this work for additional information regarding copyright ownership. 53bedc087SDawid Weiss The ASF licenses this file to You under the Apache License, Version 2.0 63bedc087SDawid Weiss the "License"); you may not use this file except in compliance with 73bedc087SDawid Weiss the License. You may obtain a copy of the License at 83bedc087SDawid Weiss 93bedc087SDawid Weiss http://www.apache.org/licenses/LICENSE-2.0 103bedc087SDawid Weiss 113bedc087SDawid Weiss Unless required by applicable law or agreed to in writing, software 123bedc087SDawid Weiss distributed under the License is distributed on an "AS IS" BASIS, 133bedc087SDawid Weiss WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 143bedc087SDawid Weiss See the License for the specific language governing permissions and 153bedc087SDawid Weiss limitations under the License. 163bedc087SDawid Weiss --> 173bedc087SDawid Weiss 18c7697b08STomoko Uchida# JRE Version Migration Guide 19c7697b08STomoko Uchida 20c7697b08STomoko UchidaIf possible, use the same JRE major version at both index and search time. 21c7697b08STomoko UchidaWhen upgrading to a different JRE major version, consider re-indexing. 22c7697b08STomoko Uchida 23*08c03566SDawid WeissDifferent Java versions may implement different versions of Unicode, 24c7697b08STomoko Uchidawhich will change the way some parts of Lucene treat your text. 25c7697b08STomoko Uchida 26*08c03566SDawid WeissAn (outdated) example: with Java 1.4, `LetterTokenizer` will split around the 27*08c03566SDawid Weisscharacter U+02C6, but with Java 5 it will not. This is because Java 1.4 28*08c03566SDawid Weissimplements Unicode 3, but Java 5 implements Unicode 4. 29c7697b08STomoko Uchida 30*08c03566SDawid WeissThe version of Unicode supported by Java is listed in the documentation 31*08c03566SDawid Weissof java.lang.Character class. For reference, Java versions after Java 11 32*08c03566SDawid Weisssupport the following Unicode versions: 33c7697b08STomoko Uchida 34*08c03566SDawid Weiss * Java 11, Unicode 10.0 35*08c03566SDawid Weiss * Java 12, Unicode 11.0 36*08c03566SDawid Weiss * Java 13, Unicode 12.1 37*08c03566SDawid Weiss * Java 15, Unicode 13.0 38*08c03566SDawid Weiss * Java 16, Unicode 13.0 39*08c03566SDawid Weiss * Java 17, Unicode 13.0 40c7697b08STomoko Uchida 41c7697b08STomoko UchidaIn general, whether you need to re-index largely depends upon the data that 42c7697b08STomoko Uchidayou are searching, and what was changed in any given Unicode version. For example, 43c7697b08STomoko Uchidaif you are completely sure your content is limited to the "Basic Latin" range 44c7697b08STomoko Uchidaof Unicode, you can safely ignore this. 45