bsh binary package in Ubuntu Focal amd64

 BeanShell is a small, free, embeddable, Java source interpreter with object
 scripting language features, written in Java. BeanShell executes standard Java
 statements and expressions, in addition to obvious scripting commands and
 syntax. BeanShell supports scripted objects as simple method closures like
 those in Perl and JavaScript(tm).
 .
 You can use BeanShell interactively for Java experimentation and debugging or
 as a simple scripting engine for you applications. In short: BeanShell is a
 dynamically interpreted Java, plus some useful stuff.

Source package