add Java example on manual dependency declaration

doc/manual/src/architecture/store/path.md

@@ -83,6 +83,8 @@ Doing it at build time and persisting references in the store object avoids repe
 ::: {.note}
 In practice, it is sometimes still necessary to declare certain dependencies explicitly, if they are to be preserved in the build result's closure.
 This depends on the specifics of the software to build and run.
+
+For example, Java programs are compressed after compilation, which obfuscates any store paths they may refer to and prevents Nix from automatically detecting them.
 :::
 
 ## Input Addressing {#input-addressing}