You can download the plugin at: https://sourceforge.net/projects/jext/files/OldFiles/antwork_plugin.zip/download
You have to enable the Jext Console to see the Apache Ant output (menu: Edit→Options…–General Panel), because Ant messages are redirected to the Jext console.
You can configure the Ant call in the Jext menu: Edit→Options…– Plugin Options–Antwork Plugin Panel; here you can set Ant home directory and the path to your build file.
You can start AntWork in the menu: Plugins→Ant→Work Now! In the appearing dialog box you can enter the target which you want to compile.
If a javac error occurs in the Ant run, an error list opens within Jext. With a
double click on the error message you jump to the error in the specified Java source file.