This always confused me as a newer developer. Vendors competed with each other with different JavaEE implementations (WebSphere, Glassfish etc) that all conformed to the same interface and provided everything including the kitchen sink, but what really differentiated the products were vendor-specific features that require you to go outside the interface, but if you tried to use that stuff, another senior developer would tell you that we can't marry our implementation to a specific vendor... meanwhile, literally every company you go to uniformly uses Spring and Hibernate, and both will inevitably require you to not pretend that they're dumb implementations of javax.inject and javax.persistence.
Small programs can be written in java. It's a general purpose programming language. You could write grep in java.
But I thought we were talking about Java:
"For example Java programs are comparatively slow to boot up."
This distinction is reflected in even small design details. For example Java programs are comparatively slow to boot up. If you're mostly used to the Unix way of repeatedly piping the STDIN/STDOUT of small utilities in an interactive command line, this is painfully inconvenient.
But if your workflow involves a monolithic server that manages every component of the business logic in a single process, then 5 second boot times aren't really a big deal. Because maybe you bounce the server once a week at most.