Attempt to study Data Structures, Optimization and Algorithms related topics!
- For these courses one should configure GIT for handle projects.
git config --global http.postBuffer 524288000.git config --global core.longpaths true.
All course material from Java Multithreading, Concurrency & Performance Optimization by Michael Pogrebinsky and Top Developer Academy LLC.
While working in the 🏛️Nordea🏛️, we were working with an old legacy system that was making two concurrent calls to a shared resource, causing inconsistent results that only appeared sometimes. The issue was subtle and difficult to reproduce, making it even harder to diagnose. What made it even harder was not runnable on our local environment! 🐟
A recent course I had taken on Java Multithreading Concurrency And Performance Optimization proved invaluable. It helped me identify the race condition and apply the
synchronizedkeyword correctly to control access to the critical section. With proper thread coordination in place, the system stabilized without requiring a major rewrite of the legacy code. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with 
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Introduction. ✅
- Section 02 - Threading Fundamentals - Thread Creation. ✅
- Section 03 - Threading Fundamentals - Thread Coordination. ✅
- Section 04 - Performance Optimization.
⚠️ In progress!⚠️ - Section 05 - Data Sharing Between Threads. ✅
- Section 06 - The Concurrency Challenges & Solutions.
⚠️ In progress!⚠️ - Section 07 - Advanced Locking.
- Section 08 - Inter-Thread Communication.
- Section 09 - Lock-Free Algorithms, Data-Structures & Techniques.
- Section 10 - Threading Models for High Performance IO.
- Section 11 - Virtual Threads and High-Performance IO.
- Section 12 - Beyond Multithreading - Final Lecture.
- Additional - Turun yliopisto threads/säikeet.
-
Add the coding exercises to the chapters
-
Get know to binary tree, before advancing the
ReentrantReadWriteLock. -
Add the solution exercises to the list!
-
Add the exercise and comments for the
We_Can_See_That_We_Dont_Have_The_Access_To_The_Main_Frame.PNG, if you have patience. -
Additional go thought Future.
-
Additional go thought
synchronizedkeyword. -
Go thought the definition of the
throughputchapter. -
Remove the files archive files when course is finished!
-
After this course ask yourself, how is the single treated programming different from the multithreaded programming?
Cleaning process of the quizes and the exercices!
- Cleaning the numbering from the exercise and quizes, they should be
01rather than1chapter by chapter:- Chapter 01.
- Chapter 02.
- Chapter 03.
- Chapter 04.
- Chapter 05.
- Chapter 06.
- Chapter 07.
- Chapter 08.
- Chapter 09.
- Chapter 10.
- Chapter 11.
- Chapter 12.
Cleaning process the images names!
- Cleaning the images in the format
Image_Next_Number, this will be chapter by chapter:- Chapter 01.
- Chapter 02.
- Chapter 03.
- Chapter 04.
- Chapter 05.
- Chapter 06.
- Chapter 07.
- Chapter 08.
- Chapter 09.
- Chapter 10.
- Chapter 11.
- Chapter 12.
Cleaning the images with the link and right alt tag!
- Bigger ink in the pictures, this will be chapter by chapter:
- Chapter 01.
- Chapter 02.
- Chapter 03.
- Chapter 04.
- Chapter 05.
- Chapter 06.
- Chapter 07.
- Chapter 08.
- Chapter 09.
- Chapter 10.
- Chapter 11.
- Chapter 12.
- Section 01:
- Section 02:
- Quiz:
- Coding Exercise:
- Section 03:
- Section 04:
- Section 05:
- Section 06:
- Section 07:
- Section 08:
- Section 09:
- Section 10:
- Section 11:
- Section 12:
All course material from Multithreading, Parallel & Asynchronous Coding in Modern Java by Pragmatic Code School.
During a live technical demonstration at Evitec Solutions, I was asked to solve a puzzle involving a Java problem that required clean data processing logic. Under normal circumstances, it was a problem perfectly suited for Java Streams, but the pressure of the live session caused me to overlook that approach. 🐟
That moment became a turning point. It pushed me to deeply pursue a course on Modern Java, where I strengthened my understanding of streams, functional patterns, and expressive problem-solving techniques. The experience helped me regain confidence and sharpen my ability to apply the right abstractions even in high-pressure situations. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Getting Started With the Course.
- Section 02 - Course Slides.
- Section 03 - Getting Started with Parallel and Asynchronous Programming.
- Section 04 - Course Project Setup.
- Section 05 - Threads, Future, ForkJoin and its Limitations.
- Section 06 - Getting Started with Parallel Streams.
- Section 07 - Build Retail Checkout Application using Parallel Streams.
- Section 08 - Parallel Streams - Under the Hood.
- Section 09 - Parallel Streams - Threading Model & Common ForkJoin Pool.
- Section 10 - Parallel Streams - Summary.
- Section 11 -
CompletableFuture. - Section 12 - Exploring
CompletableFutureFunctions. - Section 13 - Build ProductService Application using
CompletableFuture. - Section 14 - Combining Streams and
CompletableFuture. - Section 15 - Exception Handling/Recovery in
CompletableFuture. - Section 16 - Implement Exception Handling/Recovery in ProductService.
- Section 17 -
CompletableFuture& Threadpool. - Section 18 - Threads and Async Overloaded Methods in
CompletableFuture. - Section 19 - Build Restful API Client using Spring
WebClientandCompletableFuture. - Section 20 - Handle Multiple
CompletableFutures -anyOf(),allOf().
- Add some.
Course map for the Modern Java Courses!
- You can take this course first: Modern Java - Learn Java 8 features by coding it.
- You can take this course second: Multithreading, Parallel & Asynchronous Coding in Modern Java.
All course material from Modern Java - Multithreading in Java using Virtual Threads by Pragmatic Code School.
Once in a lifetime, i interviewed with 🔴Polar🔴 for an Advanced Java role, and on part of the technical discussion immediately dove into multithreading, concurrency, and performance optimization. They asked about thread pools, synchronization strategies, deadlocks, optimizing CPU-bound versus IO-bound operations, and even Virtual Threads in Java. The questions were challenging and required more than just textbook knowledge — they wanted practical understanding of real-world thread behavior. 🐟
Thanks to a recent course on Modern Java - Multithreading in Java using Virtual Threads, I could confidently discuss thread-safe collections, locks, executor frameworks, and the advantages of Virtual Threads for scalable, lightweight concurrency. Even though I was not chosen for the position, the interview drove me to deeply pursue these concepts, strengthening my skills and confidence for future challenges. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
We are using 
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Getting Started With the Course. ✅
- Section 02 - Course Slides and Source Code. ✅
- Section 03 - Getting Started with Java Threads (Platform Threads). ✅
- Section 04 - Getting Started with Virtual Threads. ✅
- Section 05 - Future and CompletableFuture. ✅
- Section 06 - Structured Concurrency using Virtual Threads (Preview Feature). ✅
- Section 07 - HTTP calls using Virtual Threads. ✅
- Section 08 - Using Futures with Virtual Threads. ✅
- Section 09 - Build a Spring Boot Application using Virtual Threads. ✅
- Section 10 - Load Test using
ab– Apache HTTP server benchmarking tool. ✅
- Original Repo!
- Section 04:
All course material from Java Application Performance Tuning and Memory Management by from Matt Greencroft ... Sir Matt Greencroft and Virtual Pair Programmers.
Add here story.🐟
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
We are using
If the content sparked 🔥 your interest, please consider starting the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Chapter 01 - Introduction. ✅
- Chapter 02 - Just In Time Compilation and the Code Cache.
⚠️ In progress!⚠️ - Chapter 03 - Selecting the JVM.
- Chapter 04 - How memory works: the stack and the heap.
- Chapter 05 - Passing objects between methods.
- Chapter 06 - Memory exercise.
- Chapter 07 - Escaping References.
- Chapter 08 - Memory Exercise.
- Chapter 09 - The Metaspace and internal JVM memory optimisations.
- Chapter 10 - Tuning the JVM’s Memory Settings.
- Chapter 11 - Introducing Garbage Collection.
- Chapter 12 - Monitoring the Heap. ✅
- Chapter 13 - Analyzing a heap dump. ✅
- Chapter 14 - Generational Garbage Collection.
- Chapter 15 - Garbage Collector tuning & selection.
- Chapter 16 - Using a profiler to analyse application performance.
- Chapter 17 - Assessing Performance.
- Chapter 18 - Benchmarking with JMH.
- Chapter 19 - Performance and Benchmarking Exercise.
- Chapter 20 - How Lists Work.
- Chapter 21 - How Maps Work.
⚠️ In progress!⚠️
- Remove the
Codesfolder after course is finished! - Check the content from other student, if there is missing or broken material. Link.
- Heap Dump Analysis Using Eclipse MAT. [Link](Heap Dump Analysis Using Eclipse MAT).
- Do the chapters
The structure of this course. - Finish this after this course is finished
Solving Memory Leaks in the JVM. (add here the link) - Read thought. Link.
- Check this memory leak course after this course. Link.
- Check second this memory leak course after this course. Link.
- Check third this memory leak course after this course. Link.
- Check Java Memory Leaks by Victor Rentea. Link.
- Check. Link.
- Section 01:
- check this one.
- Section 02:
- Example:
- FIx the links
- Logs:
- Fix the links
- Example:
All course material from Solving Memory Leaks in the JVM by Kirk Pepperdine!
Add story here. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 -
⚠️ In progress!⚠️
- Todo.
_Caption.png)
_Description.PNG)
All course material from A Comprehensive Introduction to Java Virtual Machine (JVM) by Dheeru Mundluru.
Once I saw one 👓requirement👓 in the job posting, this lead me get more comfortable at the JVM internals. 🐟
"How you would tune the JVM for Garbage Collection (GC) overhead in latency-sensitive applications?" 🐟
Sony evaluates candidates on real-world scalability, debugging under pressure, and system performance rather than just "textbook answers". 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Background ~ A High-level Overview on JVM.
⚠️ In progress!⚠️ - Section 02 - Lifetime of a Type.
- Section 03 - Reflection.
- Section 04 - JVM Memory, Garbage Collection, and Bytecode Instructions.
- Section 05 - Strings & JVM.
- Section 06 - Bonus Chapter.
- After this answer, the questions from Sony!
- After this check the blog JVM Anatomy Quarks!
The requirements, which drove me to pursies this course, from Sony!
All course material from Data Structures and Algorithms with Visualizations with Java by from Dinesh Varyani.
Add here some
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
Main: YouTube Source.
Optional: freeCodeCamp.
Optional: YouTube Source.
If the content sparked 🔥 your interest, please consider starting the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 00 - Data Structures and Algorithms with Visualizations. ✅
- Section 01 - Introduction to Data Structures. ✅
- Section 02 - Introduction to Algorithms. ✅
- Section 03 - Introduction to Algorithm Analysis. ✅
- Section 04 - Time Complexity of an Algorithm. ✅
- Section 05 - Space Complexity of an Algorithm. ✅
- Section 06 - Asymptotic Analysis of an Algorithm. ✅
- Section 07 - Asymptotic Notations | Omega, Theta and Big O Notations. ✅
- Section 08 - Types of Asymptotic Notations. ✅
- Section 09 - Analysis and Rules to calculate Big O notation. ✅
- Section 10 - Calculating Time complexity of Constant Algorithm (Big O). ✅
- Section 11 - Calculating Time complexity of a Linear Algorithm (Big O). ✅
- Section 12 - Calculating Time complexity of a Polynomial Algorithm (Big O). ✅
- Section 13 - Introduction to One-Dimensional Array. ✅
- Section 14 - Declaration and Initialization of a One-Dimensional Array. ✅
- Section 15 - Adding or Updating elements in a One-Dimensional Array | Implementation. ✅
- Section 16 - How to print elements of an Array in Java? | Animation. ✅
- Section 17 - How to print elements of an Array in Java? | Implementation ✅
- Section 18 - Remove Even Integers from an Array | Animation | Coding Interview Question. ✅
- Section 19 - Remove Even Integers from an Array | Implementation | Coding Interview Question. ✅
- Section 20 - How to Reverse an Array in Java - Animation. ✅
- Section 21 - How to Reverse an Array in Java? | Implementation. ✅
- Section 22 - How to find Minimum value in an Array? | Animation. ✅
- Section 23 - How to find Minimum value in an Array? | Implementation.
- Section 24 -
- Section 25 -
- Section 26 -
- Section 27 -
- Section 28 -
- Section 29 -
- Section 30 -
- Section 31 -
- Section 32 -
- Section 33 -
- Section 34 -
- Section 35 -
- Section 36 - Represent a Singly Linked List in Java. ✅
- Section 37 - How to Implement a Singly Linked List in Java | Data Structures and Algorithms. ✅
- Section 38 - Create a Singly Linked List in Java (Animation). ✅
- Section 39 - Create a Singly Linked List in Java (Implementation). ✅
- Section 40 - Print elements of a Singly Linked List in Java (Animation). ✅
- Section 41 - Print elements of a Singly Linked List in Java (Implementation).
- Add first captions for all the chapters, like
#someThing, so can be linked.
todo this desc.
add here the. 🐟
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Abstract data types.
- Section 02 - Introduction to Big-O.
- Section 03 - Dynamic and Static Arrays.
- Section 04 - Dynamic Array Code.
- Section 05 - Linked Lists Introduction.
- Section 06 - Doubly Linked List Code.
- Section 07 - Stack Introduction.
- Section 08 - Stack Implementation.
- Section 09 - Stack Code.
- Section 10 - Queue Introduction.
- Section 11 - Queue Implementation.
- Section 12 - Queue Code.
- Section 13 - Priority Queue Introduction.
- Section 14 - Priority Queue Min Heaps and Max Heaps.
- Section 15 - Priority Queue Inserting Elements.
- Section 16 - Priority Queue Removing Elements.
- Section 17 - Priority Queue Code.
- Section 18 - Union Find Introduction.
- Section 19 - Union Find Kruskal's Algorithm.
- Section 20 - Union Find - Union and Find Operations.
- Section 21 - Union Find Path Compression.
- Section 22 - Union Find Code.
- Section 23 - Binary Search Tree Introduction.
- Section 24 - Binary Search Tree Insertion.
- Section 25 - Binary Search Tree Removal.
- Section 26 - Binary Search Tree Traversals.
- Section 27 - Binary Search Tree Code.
- Section 28 - Hash table hash function.
- Section 29 - Hash table separate chaining.
- Section 30 - Hash table separate chaining source code.
- Section 31 - Hash table open addressing.
- Section 32 - Hash table linear probing.
- Section 33 - Hash table quadratic probing.
- Section 34 - Hash table double hashing.
- Section 35 - Hash table open addressing removing.
- Section 36 - Hash table open addressing code.
- Section 37 - Fenwick Tree range queries.
- Section 38 - Fenwick Tree point updates.
- Section 39 - Fenwick Tree construction.
- Section 40 - Fenwick tree source code.
- Section 41 - Suffix Array introduction.
- Section 42 - Longest Common Prefix (LCP) array.
- Section 43 - Suffix array finding unique substrings.
- Section 44 - Longest common substring problem suffix array.
- Section 45 - Longest common substring problem suffix array part 2.
- Section 46 - Longest Repeated Substring suffix array.
- Section 47 - Balanced binary search tree rotations.
- Section 48 - AVL tree insertion.
- Section 49 - AVL tree removals.
- Section 50 - AVL tree source code.
- Section 51 - Indexed Priority Queue | Data Structure.
- Section 52 - Indexed Priority Queue | Data Structure | Source Code.
- Add some.
All course material from Data Structures and Algorithms: Deep Dive Using Java by Goran Lochert, Tim Buchalka and Tim Buchalka's Learn Programming Academy.
I once interviewed with 🌤️Vaisala🌤️ for the Observation Network Manager NM10 role, where the technical discussion went deep into data structures and their operations. The interview challenged my understanding of trees, graphs, and time–space trade-offs in ways I hadn’t fully experienced before. Project.
Although I wasn’t selected for the position, the experience became a turning point. It drove me to truly internalize the concepts through a deep dive into Data Structures and Algorithms using Java, strengthening both my problem-solving approach and technical confidence for future challenges. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Introduction. ✅
- Section 02 - Arrays and Big-O Notation.
- Section 03 - Sort Algorithms Deep Dive.
- Section 04 - Mastering Lists in Java: Implementations and Applications.
- Section 05 - Stack Data Structures: Implementation and Use Cases.
- Section 06 - Mastering Queue Data Structures: Implementation and Applications in Java.
- Section 07 - Hash Tables: Mastering Key-Value Data Structures for Efficient Data Retrieval.
- Section 08 - Optimized Search Algorithms in Java: Linear and Binary Search.
- Section 09 - Mastering Tree Data Structures: Implementation and Optimization in Java.
- Section 10 - Mastering Heaps: Priority Queues and Heapsort Algorithm in Java.
- Section 11 - Final Section: Concluding the Course with Key Takeaways and Sets.
- Section 12 - Extra Information - Source code, and other stuff.
- Add some.
All course material from Java Data Structures & Algorithms + LEETCODE Exercises by Scott Barrett.
Once I saw one 👀requirement👀 in the job posting, I realized that my LeetCode practice wasn’t just for fun—it directly built the skills the role demanded.
"Can you design a system that efficiently handles millions of inserts, deletes, and queries per second?"
Companies like Facebook evaluate candidates on their ability to apply data structures in both coding challenges and real-world system design—showing that mastering arrays, trees, and hash maps isn’t just academic, it’s practical. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01: Introduction. ✅
- Section 02: Big O. ✅
- Section 03: Classes & References. ✅
- Section 04: Linked Lists.
⚠️ In progress!⚠️ - Section 05: LL: Coding Exercises.
- Section 06: LL: Interview / LeetCode Exercises.
- Section 07: Doubly Linked Lists.
- Section 08: DLL: Coding Exercises.
- Section 09: DLL: Interview / LeetCode Exercises.
- Section 10: Stacks & Queues.
- Section 11: S&Q: Coding Exercises.
- Section 12: S&Q: Interview / LeetCode Exercises.
- Section 13: Trees.
- Section 14: BST: Coding Exercises.
- Section 15: BST: Interview / LeetCode Exercises.
- Section 16: Hash Tables.
⚠️ In progress!⚠️
-
Section 02:
- Quiz:
- Coding Exercise:
-
Section 05:
- Coding Exercise:
- Coding Exercise 02: LL: Constructor.
- Coding Exercise 03: LL: Append.
- Coding Exercise 04: LL: Remove Last.
- Coding Exercise 05: LL: Prepend.
- Coding Exercise 06: LL: Remove First.
- Coding Exercise 07: LL: Get.
- Coding Exercise 08: LL: Set.
- Coding Exercise 09: LL: Insert.
- Coding Exercise 10: LL: Remove.
- Coding Exercise 11: LL: Reverse.
- Coding Exercise:
-
Section 12:
- Coding Exercise:
- Coding Exercise 40: Stack: Push for a Stack That Uses an ArrayList (** Interview Question).
- Coding Exercise 41: Stack: Pop for a Stack That Uses an ArrayList (** Interview Question).
- Coding Exercise 42: Stack: Reverse String (** Interview Question).
- Coding Exercise 43: Stack: Parentheses Balanced (** Interview Question).
- Coding Exercise 44: Stack: Sort Stack (** Interview Question).
- Coding Exercise 45: Queue Using Stacks: Enqueue (** Interview Question).
- Coding Exercise 46: Queue Using Stacks: Dequeue (** Interview Question).
- Coding Exercise:
-
Section 15:
-
Section 16:
- Quiz:
- Coding Exercise:
- ....
- Whenever there is new data structure learned → Check the cheat sheet, in reflection!
Important
Must know fundementals!
All course material from Introduction to Algorithms by Prof. Srini Devadas and Prof. Erik Demaine.
Add here some story. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Add here.
- Don't get stuck of the proofs.
Add here some story. 🐟
~ DevelopersCradle
Contains my own with my own visual notes ✍️ with some course material to enforce learning experience.
This repository is made with
If the content sparked 🔥 your interest, please consider buying the course and start learning 📖.
Note: The material provided in this repository is only for helping those who may get stuck at any point of time in the course. It is very advised that no one should just copy the solutions(violation of Honor Code) presented here.
- Section 01 - Add here.
- Don't get stuck of the proofs.
- Data Structures and Algorithms Specialization Review, is this worth it.
-
Can take this one Algorithms Specialization.
- Don't get stuck of the proofs, detail heavy.
