Java: added compiled metadata generation

tools/java/Readme.md

@@ -1 +1,11 @@
-## This directory contains script for autogeneration of metadata in rust
+## This directory contains script for autogeneration of metadata in rust
+
+To build from source cd /tools/java and 
+```
+mvn install
+```
+
+Example command on build generator 
+```
+java -jar tools\java\rust-build\target\rust-build-1.0-SNAPSHOT-jar-with-dependencies.jar BuildMetadataRustFromXml resources\PhoneNumberMetadata.xml ./test.rs metadata --const-name=test
+```