JAVA使用的Unicode版本

https://svn.apache.org/repos/asf/lucene/dev/trunk/lucene/JRE_VERSION_MIGRATION.txt

 * Java 1.4, Unicode 3.0
 * Java 5, Unicode 4.0
 * Java 6, Unicode 4.0
 * Java 7, Unicode 6.0

ref:
http://stackoverflow.com/questions/6941229/how-to-identify-programmatically-in-java-which-unicode-version-supported