Java Learning Journey: Comparator, Multithreading, Collections, Stream API

🚀 Continuing my Java Collection Framework learning series! I recently published a new video explaining different ways to fetch collection data in Java (Part-4) on my YouTube channel CodeFreeEducation. In this video, I explain multiple techniques to retrieve data from collections using both traditional and modern Java approaches. Topics covered in this video: • toString() • Ordinary for loop • For-each loop • Enumeration • Iterator • ListIterator • Spliterator • Lambda expressions • Method reference (forEach) • Streams 📂 Java Complete Notes: https://lnkd.in/gr5k28Yh 💻 Code Reference (GitHub): https://lnkd.in/g245HdWv 🎥 Watch the video here: https://lnkd.in/gmKG_Gce #Java #JavaProgramming #JavaCollectionFramework #JavaStreams #Iterator #CodeFreeEducation

Today I Learned – Object Orientation Rules & Main Method in Java While learning Java, I explored how object relationships work and how a program starts execution. --> HAS-A Relationship Represents composition or aggregation, where one class contains another class object as a member. Example: Car HAS-A Engine --> DOES-A Relationship Represents behavior implementation, where a class performs behavior defined by another type using interfaces or abstract classes. Example: Bird DOES-A Flyable --> Main Method in Java The entry point of a Java application where the Java Virtual Machine starts program execution. Syntax: public static void main(String[] args) Breakdown: • public → Accessible everywhere • static → Can be executed without creating an object • void → Does not return a value • main → Method recognized by JVM to start execution • String[] args → Used to receive command-line arguments #JavaDeveloper #ObjectOrientedProgramming #OOP #JavaLearning #BackendDevelopment #CodingJourney #100DaysOfCode #LearningInPublic #DeveloperCommunity #FutureDeveloper #TechCareer

Sudoku Solver: Built a Java program that solves Sudoku puzzles automatically using backtracking. The program takes an unsolved grid and fills in the correct numbers. Concepts used: Recursion, Backtracking, Arrays #Java #Coding #Learning #DSA

Day 4 — Java Stream Practice Today’s focus was on solving a common problem using Java Streams: finding the most frequent element in a collection. Given a list of words, the task was to identify the element that appears the highest number of times. Approach: Grouped elements using Collectors.groupingBy() Counted occurrences with Collectors.counting() Streamed over the map entries Used max() with Map.Entry.comparingByValue() to find the highest frequency Extracted the result using map(Map.Entry::getKey) This exercise reinforced how Streams can simplify data processing by replacing traditional loops with a more declarative approach. Key learning: Breaking down a problem into smaller transformations makes the solution more readable and maintainable. Looking forward to exploring more real-world use cases of Java Streams. #Day4 #Java #JavaStreams #Coding #ProblemSolving #BackendDevelopment #LearnInPublic

🚀 Exploring Java Collections Framework Today I deepened my understanding of how the Java Collections Framework is structured and how different data structures like List, Set, and Queue work internally. 🔍 Key Learnings: • Difference between List, Set, and Queue • Working of ArrayList, LinkedList, HashSet, TreeSet • Importance of SortedSet and data organization • How Java manages data efficiently using collections 📊 This hierarchy diagram helped me visualize everything clearly and build a strong foundation in Java. Consistency in learning is helping me grow step by step 💪 Big thanks to Prasoon Bidua sir and REGex Software Services for guidance and support 🙏 #Java #DSA #CollectionsFramework #LearningJourney #Coding #100DaysOfCode #JavaDeveloper

Day 15/30 Explored Method Overloading in Java as part of strengthening my Core Java fundamentals. Method overloading enables compile-time polymorphism, allowing multiple methods with the same name but different parameter lists (type, number, or order). This improves code readability, reusability, and flexibility while keeping method semantics consistent. Key takeaways: ✔ Same method name, different signatures ✔ Achieved without changing return type alone ✔ Resolved at compile time → better performance than runtime polymorphism in certain scenarios Built sample implementations using: 🔹 Different parameter counts 🔹 Different data types 🔹 Type promotion cases Focusing on mastering OOP concepts step by step as part of my journey toward becoming a Software Development Engineer. #Java #OOP #MethodOverloading #CompileTimePolymorphism #SDEJourney #CodingInPublic #CoreJava

Continuing my progress in Java, I’ve recently explored some important object-oriented and structural concepts that deepen my understanding of how real-world applications are designed. Here are the topics I covered: Containment (Has-A relationship) and how objects can be composed within other classes Method Overloading for achieving compile-time polymorphism Static Import to simplify code by directly accessing static members Inheritance for creating hierarchical relationships and promoting code reusability Packages for organizing classes and maintaining scalable project structure These concepts helped me better understand how to design modular, reusable, and maintainable Java applications. Step by step, moving closer to mastering core Java and applying these concepts in real-world scenarios. #Java #OOP #Programming #LearningJourney #SoftwareDevelopment #CDAC

Another concept that appears while studying class initialization in Java is the instance block. It behaves differently from static blocks and is tied to object creation rather than class loading. Things that became clear : • an instance block runs every time an object of the class is created • it executes before the constructor • it can be used to perform common initialization steps for objects • unlike static blocks, instance blocks run for each object created • they are part of the object initialization process A simple structure shows the execution flow : class Demo { { System.out.println("Instance block executed"); } Demo() { System.out.println("Constructor executed"); } public static void main(String[] args) { Demo d = new Demo(); } } When the object is created, the instance block executes first and then the constructor runs. Understanding this order helps in seeing how Java prepares an object step by step during creation. #java #oop #programming #learning #dsajourney

🚀 Day 7/45 – Working with Strings in Java On Day 7 of my Java learning journey, I explored the concept of Strings, which are used to store and manipulate text data in programs. Strings are widely used in almost every application, from user input to data processing. 📚 What I Learned Today Today I learned: ✔ What strings are and how they are created in Java ✔ Important string methods like length(), charAt(), and toUpperCase() ✔ How to compare strings using equals() ✔ Understanding case-sensitive and case-insensitive comparisons 💻 Practice Work To strengthen my understanding, I implemented: • A program to reverse a string • A program to count characters in a string • A palindrome checker using string logic 🎯 Key Takeaway Strings are a fundamental part of programming, and mastering string manipulation is essential for solving real-world problems. Consistent daily practice is helping me build strong fundamentals step by step. #Java #Programming #LearningInPublic #CodingJourney #SoftwareDevelopment #Consistency

🚀Day 21 – Understanding Variable Scope & Memory Management in Java Today I focused on concepts that play an important role in how Java programs manage variables and memory during execution. Instead of just writing programs, I explored how variables behave in different scopes and how Java automatically manages unused objects. 📚 Concepts Covered ✔ Variable Scopes • Difference between Instance Variables and Local Variables • How instance variables belong to an object and exist throughout the object's lifecycle • How local variables exist only inside methods or blocks ✔ Garbage Collection & Finalize • Understanding how Java automatically removes unused objects from heap memory • Learning how Garbage Collector helps optimize memory usage • Exploring the concept of the finalize() method and object cleanup 💡 Key Learning Understanding variable scope and garbage collection helps developers write cleaner, memory-efficient, and more reliable programs. These core concepts are essential for mastering Java, Object-Oriented Programming, and real-world software development. I’m focusing on deep understanding of concepts instead of rushing through topics, because strong fundamentals build strong developers. #Java #CoreJava #JavaProgramming #OOP #Programming #SoftwareDevelopment #CodingJourney #LearningInPublic #DeveloperJourney #TechLearning #BackendDevelopment #FutureDeveloper #BuildInPublic #Consistency