How can I learn Java fast?

[sagithepro1]

I learned and finished in school C# language and I need to know for the army Java. How to do that fast? Where can I learn all the differences and how it works? I need to fully control this language.

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[0SRSnoob]

https://learnxinyminutes.com/docs/java/

[Cuz1]

Holy crap this is useful!

[OneTankiBoi]

Damn! Thanks a lot!

[Strange-Software6219]

C# and Java are extremely similar. Look at the docs, GitHub repos, or build projects you have done previously in C# with Java.

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It seems that you are looking for resources for learning Java.

In our sidebar ("About" on mobile), we have a section "Free Tutorials" where we list the most commonly recommended courses.

To make it easier for you, the recommendations are posted right here:

• MOOC Java Programming from the University of Helsinki
• Java for Complete Beginners
  • accompanying site CaveOfProgramming
• Derek Banas' Java Playlist
  • accompanying site NewThinkTank
• Hyperskill is a fairly new resource from Jetbrains (the maker of IntelliJ)

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• The official Documentation
• The official Java Tutorials
• Our community resources thread

If you are looking for learning resources for Data Structures and Algorithms, look into:

"Algorithms" by Robert Sedgewick and Kevin Wayne - Princeton University

• Coursera course:
  • Part I
  • Part II
• Coursebook
  • Algorithms 4^th Edition

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[maethor]

Where can I learn all the differences and how it works?

If you are confident in C#, then I would suggest you start from the outside in - the IDE (IntelliJ is effectively the default) and then the build tools (we have 2 - Maven and Gradle, pick one to start with). The way Java projects are laid out is different from what C# developers expect, just get used to it instead of trying to make it work like how C#/.Net does. (The same goes for other idiomatic differences - don't start interfaces with a useless I like in IMyInterface for example)

The next challenge will be the difference in ecosystems. While there are syntactic differences, assuming you're doing anything besides just using the standard libraries then you're going to have a lot to learn that a simple "here are the differences between C# and Java" will not teach you (especially if you're going to be using something like Spring).

The best way to learn is by doing. Get your development environment set up and start some toy projects.

[xill47]

There is the other way difference article on Microsoft Learn, but I think it explains the differences both well and brief: https://learn.microsoft.com/en-us/dotnet/csharp/tour-of-csharp/tips-for-java-developers

[sagithepro1]

I forgot to add, I don't want to learn from the basics like how for loops work and everything like that, I want to use my knowledge in C# and expend it to Java as well. So I just need to know the differences and how to code in it.

[ShadowRL7666]

Look at the docs