Defer postinst after a given package

[Fab Stz <fabstz-it@yahoo.fr>]

Hi,

I have a package B that depends on gradle, which depends on Java.
B doesn't have a dependency to Java set in d/control.

B runs a postinst script which requires Java.

At times, during installation Java is set up before B, at times after.

How can I be sure that B is always setup after Java?

By Java I mean:  openjdk-11-jre-headless:amd64 which is the one that creates the alternatives to have/usr/bin/java.

Thanks