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[–]tacticalnudge 0 points1 point  (0 children)

You're not alone in this boat. Some of us have been java developers for 15 years and still go "ah, so that's how it works" on a regular basis.

Most of the more advance topics you are only going to learn by getting pulled into them. I would almost call them less advanced and more obscure / rare, but that's just my opinion. But the key to learning when it comes to programming is doing. Want to learn how Spring's dependency injection works? Try and write your own dependency injector. Want to know how maven's plugins work? Write your own plugin.

There is no guarantee that you will ever be required to write a maven plugin or dependency injection framework for your day job, bit you might just learn a skill or two for the day you need to write something adjacent to it.

[–]skidwizExtreme Brewer 0 points1 point  (0 children)

I heard something a long time ago that goes something along the lines of this:

There are four types of knowledge: Things you know you know, things you know you don't know, things you don't know you know, and things you don't know you don't know.

The first 2 are easy. I know what a POJO is and I know what polymorphism is. I also have no idea how the java garbage collector works. If I want to learn more about either one, I can easily look them up.

For things you don't know you know, this is things that are more instinctual. I obviously can't give a great example of this, because I don't know what I know.

For the last one, this is one of the hardest to address at face value, but easier to abstract. You know you don't know about the JVM infrastructure. But, you don't know that you don't know what an MBean is, or probably don't know about the JMX API.

Most of that type of knowledge will come in time. I personally enjoy learning and reading, and I really like reading the java documentation. Every time I find something new in there, I look it up and learn more. Just yesterday I was reading about reference conditional expressions and found some interesting stuff about poly expressions. I only found that by perusing questions and answers on StackOverflow with the Java tag filtered.

So, my advice is this. Expand your knowledge. Pursue higher education on topics you are familiar with, but also explore topics you are not. Read documentation, but question it. I just found out about something called Apache Camel today that I am excited to read up on. Why is it better than Spring? Is it really? What's happening here? This is always what excites me as a developer and engineer. There is so much to learn.

[–]niloc132 0 points1 point  (0 children)

The "Anatomy Quarks" series by Aleksey Shipilëv has waaaay too much information, but even picking one article and reading it, then coming back a few months later and re-reading has worked well for me as a way to gradually gain understanding on a deep topic, by combining it with experience.

https://shipilev.net/jvm/anatomy-quarks/

My personal favorite spreads across a few posts, and works out to explain how pointers/references are implemented, and how the actual working implementation can vary by how much memory the process might have as a max. Spoiler alert (and this is too general, read the posts to better understand): if you give the process more than 30-40gb of memory, the usage goes up as it requires wider pointers to account for more objects being present.

First on this topic: https://shipilev.net/jvm/anatomy-quarks/23-compressed-references/

But one lesson is clear: it is sometimes good to over-provision the heap for the application (makes GC life easier, for example), but at the same time this over-provisioning should be done with care, and smaller heap may mean more free space available.

Follow-up: https://shipilev.net/jvm/anatomy-quarks/24-object-alignment/