document XZ for Java dependency
diff --git a/docs/index.html b/docs/index.html
index 21ec7b2..5a7b1e3 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -119,6 +119,10 @@
<p>This Antlib requires Apache Ant 1.8.0 or higher, Apache
Commons Compress 1.13 or higher and Java7 or higher.</p>
+ <p>In order to use LZMA, XZ or most of the 7z support
+ the <a href="https://tukaani.org/xz/java.html">XZ for Java</a>
+ version 1.6 or later is required.
+
<p>If you are building the Antlib from sources, run
the <code>antlib</code> target and you'll get a
file <code>ant-compress-VERSION.jar</code>. If you've
@@ -145,6 +149,8 @@
<classpath>
<pathelement location="YOUR-PATH-TO/ant-compress-VERSION1.jar"/>
<pathelement location="YOUR-PATH-TO/commons-compress-VERSION2.jar"/>
+ <!-- optional dependencies -->
+ <pathelement location="YOUR-PATH-TO/xz-VERSION3.jar"/>
</classpath>
</taskdef>
</pre>