how to use java methods in appian

You cannot use any Java in normal Appian. You can write plugins in Java.

Why do you need Java to display the size of a document? Just call document(<YOUR_DOCUMENT>, "size").

You cannot use any Java in normal Appian. You can write plugins in Java.

Why do you need Java to display the size of a document? Just call document(<YOUR_DOCUMENT>, "size").

As part of the application I'm working on, I want to display the how much disk space is used by all the documents present in the KC of the application.

If it is one application I can use call document(<YOUR_DOCUMENT>, "size").

Why is that necessary?

You have options here. First, just iterate on all the document and sum it up.

sum(
  a!foreach(
    items: folder(<YOUR_FOLDER>, "documentChildren"),
    expression: document(fv!item, "size")
  )
)

Or, store some meta data to the database and do that aggregation over there.

But even more important, check out the excellent documentation

https://docs.appian.com/suite/help/22.3/Appian_Functions.html

https://docs.appian.com/suite/help/22.3/Expressions.html

docs.appian.com/.../SAIL_Recipes.html

Thank you Stefan.

I'll try to use this approach