Installing extensions as SDKs doesn't work

[justpav05]

Hello, I tried to install the Java SDK, but as an add-on it simply does not want to integrate into Zed, even with the variable that should work

[Nyaacinth]

There's too few details avaliable from your message. So generically: If you want to use SDK extensions, you first need to disable sandbox escape (setting env var ZED_FLATPAK_NO_ESCAPE=1 in e.g. flatpak override) and declare sdk extensions usage (via env var FLATPAK_ENABLE_SDK_EXT="openjdk" or similar.) Go see README in this repo.
However, you might actually want to use other solutions that actually uses sandbox escape due to the lack of ecosystem compatibility and system integration of sandbox that might make you suffer when debugging. In this case I would recommend your system's package manager (in common distros) or Homebrew (in immutable distros.)