Learning Java with Aditya Tandon Sir: JVM, JRE, JDK

🚀 Day 48 of My Java Learning Journey Today, I explored one of the most important concepts in Java – Collection Framework 💡 📌 What I Learned: Collection Framework is a set of classes and interfaces used to store and manipulate data efficiently It was introduced in JDK 1.2 by Josh Bloch Acts as an alternative to Data Structures in Java 📊 Key Components: Interfaces → List, Set, Queue, Map Classes → ArrayList, LinkedList, HashSet, HashMap 🔥 Why Collections? ✔ Dynamic size (no fixed length like arrays) ✔ Inbuilt methods (add, remove, etc.) ✔ Efficient data handling ✔ Reduces coding effort 💻 Key Features: Allows heterogeneous data Maintains insertion order (List) Allows duplicates (List) Improves performance in real-world applications 📈 Takeaway: Collection Framework is a must-know concept for interviews and real-time development. Almost every Java application uses it! #Day48 #Java #CollectionsFramework #JavaDeveloper #LearningJourney #Coding #Programming

When I first started learning Java, garbage collection felt like magic. 1)You create objects. 2)The program get runs. 3)Unused memory gets cleaned up. But Java memory is not just one big box. Here is the simple model: * New objects start in Young Generation * Long-living objects move to Old Generation * Unused objects get removed by the Garbage Collector Example: A temporary list created inside a method usually dies young and gets cleaned quickly. But something like cache data or a session object can survive longer and move to the Old Generation. That matters because: * Young Generation collection is usually fast * Old Generation collection is heavier * Understanding both helps you reason about performance #Java #SpringBoot #BackendDevelopment #SoftwareEngineerr #javadeveloper

Day 38 of Learning Java Today, I explored how a class executes inside the JVM (Java Virtual Machine). Understanding this lifecycle really helped me see what happens behind the scenes when we run a Java program. 🔹 Class Loading   • The JVM loads the class into memory   • It brings the ".class" file into the system 🔹 Linking Phase  • Verification → Checks bytecode for errors  • Preparation → Allocates memory for static variables (default values like 0)  • Resolution → Replaces symbolic references with actual memory references 🔹 Initialization  • Static variables get their actual assigned values  • Static blocks are executed 🔹 Execution  • Methods start running and the program logic is executed 🔹 Destruction  • Objects are destroyed and memory is cleaned up by the Garbage Collector Static variables first get default values during preparation, and later their actual values during initialization. Thanks to my mentor Ashim Prem Mahto for the clear explanations and for always clearing my doubts. #Java #JVM #LearningJourney #Programming #SoftwareDevelopment #BackendDevelopment #CodingLife #JavaDeveloper #TechLearning #StudentLife

🚀 Day 22 of my Java DSA Journey Back after a short break — now continuing with consistency. Today’s problem: Merge Two Sorted Lists (LeetCode #21) 🔹 Topic: Linked List 🔹 Pattern: Two Pointer Technique 💡 Key Idea: We use two pointers to traverse both sorted linked lists and build a new sorted list by always picking the smaller node. Instead of creating new nodes, we simply adjust the existing node pointers — making the solution efficient. 🧠 Key Learning: Linked List problems are more about pointer manipulation than logic complexity. Once you understand how pointers move, problems become much easier. 📊 Complexity: • Time: O(n + m) • Space: O(1) Consistency > Perfection. Back to the grind. 🔗 GitHub Solution: https://lnkd.in/gTzbQeTV #Java #DSA #LinkedList #LeetCode #ProblemSolving #CodingJourney

Day 37 of Learning Java Today I learned something interesting Illegal Forward Reference in Java. At first, it sounded complicated, but once I understood it, it actually made a lot of sense! Here’s what I learned: 🔹 What is Illegal Forward Reference?   • It happens when you try to use a variable before it is declared.   • Java doesn’t allow referencing a variable that comes later in the code. 🔹 Why does it happen?   • Java reads code from top to bottom.   • If a variable is used before it exists, the compiler throws an error. 🔹 Example of the issue:   • Using a variable before declaring & defining it to a compile-time error. 🔹 How to fix it?   • Always declare variables before using them.   • we have to call static variable using ClassName.VarName. Thanks to my mentor Ashim Prem Mahto for the clear explanations and for always clearing my doubts. #Java #LearningJava #CodingJourney #Programming #DeveloperLife #CodeNewbie #JavaDeveloper #TechLearning #StudentLife #jvm

🔐 Mastering inheritance starts with mastering access modifiers! Understanding how public, protected, default, and private work across packages and subclasses is key to writing secure, maintainable Java code. #TapAcademy #Java #Inheritance #AccessModifiers #Encapsulation #OOP #ProgrammingTips #CleanCode

🚀 Day 8 of My Core Java Journey Today I learned about Loops & Jump Statements in Java, which are fundamental for controlling iterations and repeating tasks in programs. 🔁 Loops Covered: ➤ While Loop – Check first, then execute ➤ Do-While Loop – Execute first, then check (runs at least once, useful in menu-driven programs) ➤ For Loop – All-in-one powerful loop for initialization, condition, and update 🔄 Also explored: ✔ Nested loops and how iterations grow (n × m pattern) ✔ How loops control execution flow step by step ⚡ Jump Statements: ➤ break → stops the loop immediately ➤ continue → skips the current iteration 💡 Bonus Learning: • We can use labeled loops (outer, inner) for better control in nested loops • Understanding loop flow makes it easier to optimize logic and avoid unnecessary iterations This topic made it clear how programs handle repetition and control flow efficiently. Grateful to Rohit Negi sir, Aditya Tandon sir, and the Coder Army youtube channel for such clear explanations 🙌 Building strong Core Java fundamentals step by step 💻 #Java #CoreJava #JavaDeveloper #Programming #Loops #LearningJourney #CoderArmy

Day 3 of Java Learning Series 🔍 JDK vs JRE vs JVM (Simple Explanation) If you're starting with Java, this is one of the most important concepts 👇 🔹 JVM (Java Virtual Machine) 👉 Converts bytecode into machine code 👉 Makes Java platform-independent 🔹 JRE (Java Runtime Environment) 👉 Provides libraries + JVM to run Java programs 👉 You can run Java but NOT develop 🔹 JDK (Java Development Kit) 👉 Full package for developers 👉 Includes JRE + development tools (compiler, debugger) 💡 Simple Analogy: JDK = Kitchen (everything to cook) JRE = Kitchen + Ingredients (ready to cook) JVM = Stove (where cooking happens) 📌 Flow: .java → Compiler → .class (bytecode) → JVM → Machine Code 👉 Follow me for more Java content 🚀 #Java #CoreJava #Programming #Developers #100DaysOfCode #Coding

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 33 of Learning Java Today I learned about Return Types in Java methods, and it finally started to make sense how methods give results back! Here’s what I understood: 🔹 Every method has a return type 🔹 It tells what kind of value the method will give back 🔹 There are mainly two types: Primitive Data Types (PDT) :  • byte  • short  • int  • long  • char  • String  • float  • double  • boolean Reference Data Types (RDT) :  • Arrays  • Classes  • Interfaces  • Annotations  • Enums 🔹 A method can also return an object  🔹 The "return" keyword is used to send the value back 🔹 If nothing is returned, we use "void" Thanks to my mentor Ashim Prem Mahto for the clear explanations and for always clearing my doubts. #Java #LearningJava #ProgrammingJourney #CodingLife #JavaBasics #SoftwareDevelopment #DeveloperJourney #TechLearning #StudentLife