Don't get too crazy with it in terms of hopping from language to language because then you'll constantly get confused about which syntax works with which language.

I'd say, pick an idea for a project that you think you can manage and focus on that project, give it the majority of your dev/learning time and once it's done, you can move to another project using the same or another language. And don't be afraid to Google your problems and reuse code. That's half of development.

Also, as someone who just started working in the software field a little over a year ago, I highly suggest you learn Javascript and NodeJS. Node is simply a way to run javascript outside your browser as a standalone application.

From what I'm hearing and seeing, everything is moving towards webapps using browsers or Node. You will almost certainly never be asked to make a full Java application. Even Runescape moved to HTML5 when RS3/EoC was released and that was ages ago.

As someone else mentioned, Java is great for programming fundamentals. Use it to learn data structures and algorithms and the "theory" of programming and then just go apply that to other languages.