Gradle import fails behind corporate proxy with auth

I'm ​behind a corporate proxy that requires authentication.

When opening a Gradle project, the plugin fails to download Gradle binaries. I get code completion only for JDK classes and a notification that "classpath is incomplete". The error in logs is about connection timeout.

JRE system properties are set in vscode settings as per instructions here: https://github.com/redhat-developer/vscode-java/wiki/Using-a-Proxy

Tested with Windows and Linux.