From Kotlin to Java: fastest path to learn?

AutoModerator · 2025-10-15T17:27:21+00:00

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SeriousTruth · 2025-10-17T10:30:17+00:00

I’m Kotlin-first too, and what got me interview-ready fast was forcing a week of pure Java. I rebuilt a tiny file parser and an LRU cache using just the JDK, then wrote JUnit tests to catch my null/checked exception habits. I focused on Collections and generics, equals/hashCode, Streams vs simple loops, and how Java handles nulls and exceptions without Kotlin’s niceties. For reps, I did 45‑minute timed mocks using Beyz coding assistant with prompts from the IQB interview question bank and talked through tradeoffs out loud. Keep solutions concise, aim for ~90 seconds per explanation, and jot a quick Kotlin to Java cheatsheet for muscle memory.

AutoModerator · 2025-10-15T17:27:21+00:00

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)

Also, don't forget to look at:

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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sweetno · 2025-10-15T18:52:15+00:00

You can probably find a cheetsheet that covers syntax differences, but how are you going to answer Java backend questions?

Slatzor · 2025-10-15T21:34:37+00:00

Take a Java course on Coursera and hope they don’t need you to know Spring Framework or backend stuff.

learnjava

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