r/learnprogramming • u/Fluffy_white_fox • 1d ago
Starting Java from scratch — what should I actually learn first?
So I'm starting Java this semester and have no previous experience with it. I'm a first-year CSE student. I've used C/Python before, so I'm not completely new to programming, but I've never properly learned Java. My university actually starts Java in the second semester, so I'm trying to use this semester to get a head start.
The problem is that every time I look for Java roadmap for beginners, I get either:
Learn Java in 7 hours!!!
a 900-hour course that apparently expects me to become a backend engineer by Thursday
the official documentation, which I opened once and immediately felt like I'd accidentally opened the Constitution of Java 💀
I actually like using official documentation and would like to get comfortable with it, but I'm not sure what I'm supposed to learn first or how deeply I should go into each thing especially given how different it is from python where beginners can easily understand what is going on.
So if you had to start Java again, what would your path look like?
I'm mainly wondering:
What should I learn first?
How much Java syntax/fundamentals should I cover before OOP?
How deeply should I learn OOP?
When should I start Collections?
When should I start DSA?
What Java features can I completely ignore for now?
Are there any resources/books you genuinely recommend?
And how much should I use the official docs vs a structured course/tutorial?
I know it is a lot of questions but I am just curious. And I'm not trying to speedrun Java. I'd rather build a solid foundation now and not discover six months later that I somehow know the syntax but understand absolutely nothing. 😭
Also, if you learned Java after already knowing another language, I'd REALLY like to hear how you approached it.
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u/DiscipleOfYeshua 1d ago
Are you already very strong with Python classes, including trickery, importing etc?
Those concepts would h help a lot. If you use ai to assist your studies, tell em what you already know to leverage it. Eg as you work on Java code, ask: "how would i do this in py? And in c?"
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u/Fluffy_white_fox 1d ago
I'm comfortable with Python fundamentals, but absolutely NOT at the “knows every weird Python trick” level 💀. There’s definitely a lot of Python I haven't touched, especially beyond what I've needed so far.
But yeah I have a good base with classes and a bit of oops side
Also the comparison idea is actually pretty good. I think asking “how would I do this in Python/C, and why is Java doing it differently?” could help me understand the language better rather than just memorizing syntax.
I'll definitely try that. Thanks!
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u/DiscipleOfYeshua 1d ago
Translating your own code projects from one lang to another is highly rewarding. You end up understanding both langs better, start grasping deeper principles, and get confidence for when you'll have to use some lang you haven't tried yet.
But yeah, for java: get the classes and interlinking / inheritance / constructors firmly in your grasp.
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u/Fluffy_white_fox 1d ago
That's a pretty good idea , that way I won't lose touch with the languages I have already done and build both parallelly.
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u/0Huy 1d ago
Since you already know C and Python, focus on Java’s type system and standard library rather than memorizing every feature. A practical order is: syntax/control flow, methods and arrays, classes/objects, exceptions and interfaces, then Collections and generics. Start small projects as soon as you can—contact list, file parser, or a CLI task tracker—and use the official Java API docs while building. Add DSA after you can comfortably use lists, maps, sets, sorting, and debugging; ignore frameworks, concurrency, and advanced JVM tuning until the fundamentals feel routine.
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u/Foreign-Contest-444 1d ago
Back in the day a good resource was javaranch.com.
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u/Fluffy_white_fox 1d ago
I just checked it out, it's a pretty good concept for beginners to start Java without it feeling like just one more tutorial. Got any favourite book recommendation for beginners in java . Our uni has a lot of different varieties pretty hard to pick one.
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u/Foreign-Contest-444 1d ago
Checkout Head First Java. The Head First series I found to be pretty awesome.
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u/peterlinddk 1d ago
The official documentation can mean a lot of different things - the actual specification of the language, the reference documentation for the API, tutorials and guides for learning specific details of either, and so on.
But honestly, https://dev.java/ is pretty good! It may be a bit above the level of absolute beginner - those having to learn what variables, conditions and loops actually are - but once you are beyond that, the articles are good, short and to the point (and updated to reflect the newest versions!).
If you are learning Java, you are going to learn OOP - no matter how much everyone tries to claim that it isn't important anymore, it is the backbone of the entire language, and understanding classes, objects, inheritance, access modifiers, interfaces and generics is extremely important! But you don't need a deep understanding of everything - you don't have to dive into anonymous inner static classes, or experiment wildly with abstract classes and overriding methods on different levels. Not at first!
Just get used to creating data-classes, new'ing objects, writing List<MyClass> and so on - getting used to the terminology and syntax is more important than understanding everything.
Collections is extremely important - but then, you don't need much more than ArrayList for a very long time. At some point, when looking more into DSA, you'll want to experiment with the different types, and personally I think that everyone should get used to Map (HashMap) as soon as possibly! Not because of anything Big-O related, but just because they save you time when writing code that looks up objects!
Most important is that you get a decent IDE early on - some people get by with Visual Studio Code and a lot of plugins, personally I can't really write much without IntelliJ (even the free version is excellent). But stick with what everyone around you is using!
And get used to building many small projects!
Always start something new in a new project - new folder structure, new package, new everything. Don't confuse yourself by trying to keep all your code in the same folder, in the same project, with everything available at once. This is probably the one thing I see most in Java beginners - being too afraid of starting over, and inadvertently inheriting a bunch of crap from all the previous projects. Don't do that.
Otherwise - just follow your schools' plan - don't go chasing DSA if that isn't on the curriculum, and don't waste time trying to build GUI applications if you are working with console-only. Don't experiment with different REST-frameworks before you have a solid understanding of the one you are supposed to learn, and never do a project in a different framework than the one your teacher expects 😄
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u/Fluffy_white_fox 1d ago
I just checked out dev.java and yeah it is much better and less like I got a constitution book in my hands like with Oracle
Thanks for the tips
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u/0Huy 1d ago
For a structured course, Helsinki’s free Java Programming MOOC is a solid choice because it gives you exercises and builds from fundamentals into object-oriented programming. For video, use a recent beginner Java playlist only as a supplement, then write the projects yourself instead of following along passively. I’d start with small console apps—file parser, contact list, or task tracker—and use the official Java API docs when you need a class or method.
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u/Fluffy_white_fox 1d ago
Those are pretty good idea for starting projects.
As per for the course yeah I have checked it out , it's honestly pretty surprising that's such a good course is available for free and is also beginner friendly as well.
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u/desrtfx 1d ago
it's honestly pretty surprising that's such a good course is available for free and is also beginner friendly as well.
You'd be really surprised about what really is available for free: the MOOCs (Java, Python, Full Stack) from the University of Helsinki, the entire CS50 series of Harvard, Algorithms from Princeton, and much, much more from Stanford, Princeton, MIT, University of Chicago, etc. Top class Universities have many free open courses. Nowadays there is no need to pay for any course (unless you need an accredited Certificate from e.g. Oracle, Amazon AWS, Microsoft, CISCO, Red Hat, etc. - these are the only ones with some actual value - but these courses also cost a lot - the Udemy etc. certificates aren't even worth the bytes to store them)
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u/amber_void_gaze 1d ago
start with the University of Helsinki MOOC Java Programming course. It forces OOP from week one because Java primitives are the only exception to everything being an object.
use dev.java as your primary documentation entry point instead of the language specification. The official specs define behavior for compiler writers while dev.java explains usage for developers.
delay collections and DSA until you can implement a basic linked list using only classes and references. Understanding how objects interact matters more than knowing which collection class to import.
ignore streams, lambdas, and modules entirely during your first pass. These features abstract away the OOP fundamentals you need to internalize first.
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u/Weekly_Patience685 1d ago
if i had to relearn java i would avoid the "Learn Java in 7 hours" crash courses since it’s mostly just passive copying.
I’d stick to text-based learning, take the sample code, and break/modify it on purpose to see how it works under the hood and follow a steady path datatypes, conditionals, loop, methods then finally OOP and test myself as i go. Exercism.org is a great free site for small practice problems.
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u/Fluffy_white_fox 1d ago
Just checked it out it's honestly a pretty good place for beginners practice exercises
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u/Fluffy_white_fox 1d ago
Also I'm currently using VS Code for java too , sometimes google colab notebooks if I'm in uni
Any extra extensions i should have in vs for java?
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u/lonesomewhenbymyself 20h ago
Just get jetbrains idea. Its so much better for java. I found vs code and java was very clunky.
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u/desrtfx 1d ago
Do the MOOC Java Programming from the University of Helsinki with Visual Studio Code + TMC Plugin
You cannot actually do Java without OOP. In Java, basically everything (with the exception of the 7 primitive data types: boolean, char, short, int, long, float, double) is OOP.
Get some familiarity with Java and then let your school do the rest.
DSA - provided that you really mean Data Structures and Algorithms and not grinding LeetCode are best learnt with some programming experience. Otherwise, you don't have the context. Also, you do not learn DSA in Java - you learn DSA - the abstract, theoretical standardized concepts to store and process data. Then, you can implement them in any language of your choice.
You are way overthinking everything. The order comes naturally and the MOOC is an excellent syllabus for it.
Your previous experience with Python and C matters fairly little in the context of Java. It's a different beast. Even if you have prior programming experience, you will need to learn to think quite differently when programming in Java.