build libreoffice ocurred "Ant does not work"

OS on Virtualbox : Ubuntu 18.04

When I try to build the libreoffice on Ubuntu 16.04 and Ubuntu 18.04, they both occurred “Ant does not work”.

I check with ant -verbose, then get error message :

Apache Ant(TM) version 1.10.3 compiled on July 19 2018 
Trying the default build file: build.xml
Buildfile: build.xml does not exist!
Build failed

More information about ./’s error message :

checking for ant... /usr/bin/ant
checking if /usr/share/ant/bin/ant works... configure: error: Ant does not work - Some Java projects will not build!
Error running configure at ./ line 296.

Somebody know how to create/write the Buildfile ?

better ask at #libreoffice-dev

Thank for your comment, let me try it.