Recruiting Java developers is easy mode, there are rather large consultancies and similar suppliers that will sell or rent them to you in bulk so you don't need to nag with adverts to the same extent as with pythonistas and rubyists and TypeScript.
But there is likely some decline for Java. I'd bet Elixir and Erlang have been nibbling away on the JVM space for quite some time, they make it pretty comfortable to build the kind of systems you'd otherwise use a JVM-JMS-Wildfly/JBoss rig for. Oracle doesn't help, they take zero issue with being widely perceived as nasty and it takes a bit of courage and knowledge to manage to avoid getting a call from them at your inconvenience.
Speaking as someone who ended up in the corporate Java world somewhat accidentally (wasn't deep in the ecosystem before): even the most invested Java shops seem wary of Oracle's influence now. Questioning Oracle tech, if not outright planning an exit strategy, feels like the default stance.
Most such places probably have some trauma related to Oracle now. Someone spun up the wrong JVM by accident and within hours salespeople were on the phone with some middle manager about how they would like to pay for it, that kind of thing. Or just the issue of injecting their surveillance trojans everywhere and knowing they're there, that's pretty off-putting in itself.
Which is a pity, once you learn to submit to and tolerate Maven it's generally a very productive and for the most part convenient language and 'ecosystem'. It's like Debian, even if you fuck up badly there is likely a documented way to fix it. And there are good libraries for pretty much anything one could want to do.
But there is likely some decline for Java. I'd bet Elixir and Erlang have been nibbling away on the JVM space for quite some time, they make it pretty comfortable to build the kind of systems you'd otherwise use a JVM-JMS-Wildfly/JBoss rig for. Oracle doesn't help, they take zero issue with being widely perceived as nasty and it takes a bit of courage and knowledge to manage to avoid getting a call from them at your inconvenience.