This is a minimal example for a sequence diagram:
@startuml example
bob->anne: hello
The Visual Studio Code plugin PlantUML shows no error, but the java app cannot create an image:
java -jar "plantuml-mit-1.2024.6.jar" -tpng exmaple.plantuml
Warning: no image in exmaple.plantuml
No diagram found
The @enduml tag was missing and the warning not too precise.
The following works with the vscode extension as well as the command line java app:
@startuml example
bob->anne: hello
@enduml