Java Functional Interfaces Explained with Real-Life Examples

Day 25 -What I Learned In a Day(JAVA) Today I learned about conditional and control statements in Java, which allow programs to make decisions, repeat tasks, or alter the flow of execution. Three Types of Control Statements in Java: *Decision Statements (Decision Making) Used to execute code based on conditions. Examples: if / if-else / nested if-else – Executes code if condition is true or false. switch – Executes code based on the value of a variable. *Looping Statements: Used to repeat a block of code multiple times. Examples: for, while, do-while. *Jump Statements: Used to alter the normal flow of execution in loops or methods. Examples: break, continue, return. Today I Practiced 20 questions based on the decision making statement if,else. Practiced 👇 #Java #IfElse #ConditionalStatement #NestedIfElse #DecisionMaking #LogicalOperators #ComparisonOperators #JavaPractice #ProgrammingBasics #FlowControl #TodayILearned #CodingPractice

Revision | Day 6 – Multithreading Today I explored the basics of Multithreading in Java and why it is important for building high-performance applications. What is Multithreading? Multithreading allows a program to execute multiple threads (smaller units of a process) simultaneously. It helps improve application performance and better CPU utilization. Thread vs Runnable There are two main ways to create threads in Java: 1. Extending Thread class class MyThread extends Thread { public void run() { System.out.println("Thread is running"); } } 2. Implementing Runnable interface (recommended) class MyRunnable implements Runnable { public void run() { System.out.println("Thread is running"); } } Runnable is preferred because Java supports single inheritance but multiple interfaces. Synchronization When multiple threads access shared resources, it may cause inconsistent results. Synchronization ensures that only one thread accesses the critical section at a time. Example: synchronized void increment() { count++; } Deadlock Deadlock occurs when two or more threads wait for each other to release resources, causing the program to freeze. Example scenario: Thread 1 → lock1 → waiting for lock2   Thread 2 → lock2 → waiting for lock1 Both threads get stuck forever. Key takeaway: Understanding multithreading is essential for building scalable backend systems and handling concurrent requests efficiently. #Java #Multithreading #BackendDevelopment #JavaDeveloper #LearningInPublic

A Tiny Java Mistake That Causes a Compile Error ❗ A Pitfall in Java: Why int i =08 doesn't work? Many developers get confused when Java throws an error for 08. The reason is simple but often overlooked. If a number starts with 0, Java treats it as an Octal number! (Base 8). Octal numbers only allow digits 0–7. That’s why: 08 ❌ 09 ❌ 010 ✔ (equals 8 in decimal) Small Java details like this can save hours of debugging. Swipe through the carousel to understand this Java concept clearly. #Java #JavaDeveloper #Programming #CodingTips #SoftwareEngineering #TechLearning #JavaForbeginners #JavaTipsForProfessionals

Day 3 / 60 — Understanding Java Strings & Core OOP Concepts Continuing the 60-day journey to become a strong Java Spring Boot Developer. Today’s focus was on arrays, strings, and core object-oriented concepts that form the backbone of Java development. Covered: • Drawbacks of Arrays • Arrays of Objects • Enhanced For Loop • Strings in Java • Mutable vs Immutable Strings • StringBuilder & StringBuffer • Encapsulation • Getters and Setters • this keyword • Constructors One key takeaway today: Strings in Java are immutable, which improves security and predictability, while classes like StringBuilder allow efficient modification when needed. Building stronger fundamentals step by step. #Java #SpringBoot #BackendDevelopment #LearningJourney

Day 1/100 — What is Java? ☕ Most beginners start writing Java code without understanding what actually runs their program. Let’s fix that today. When you write Java code, it doesn’t directly talk to Windows or Mac. First, the code is compiled into a bytecode (.class file) . This bytecode is then executed by the JVM (Java Virtual Machine). The JVM acts like a translator between your program and the operating system. That's the reason Java follows the famous principle: “Write Once, Run Anywhere.” JVM vs JRE vs JDK • JVM → Executes Java bytecode • JRE → JVM + standard libraries (String, Math, Collections, etc.) • JDK → JRE + developer tools like javac compiler 👉 If you're a developer, always install the JDK because it includes everything needed to build and run Java programs. Today's Challenge 1. Install the JDK 2. Create a file HelloWorld.java 3. Compile using: → javac HelloWorld.java 4. Run using: → java HelloWorld For More Clarity Check Out this Vedio:- https://lnkd.in/g4Tp5UMp Post your output screenshot in the comments — I’ll check it! 👇 hashtag #Java #100DaysOfJava #CoreJava #JavaDeveloper #Programming #LearnInPublic

Method Overloading in Java -> more than just same method names Method overloading allows a class to have multiple methods with the same name but different parameter lists. Java decides which method to call based on the method signature, which includes: • Number of parameters • Type of parameters • Order of parameters One important detail many people miss: Changing only the return type does not create method overloading. Why does this concept matter? Because it improves code readability and flexibility. Instead of creating different method names for similar operations, we can keep the same method name and let Java decide the correct one during compile time. That’s why method overloading is also called compile-time polymorphism. Small concepts like this form the foundation of how Java’s Object-Oriented Programming model really works. #Java #JavaProgramming #OOP #BackendDevelopment #CSFundamentals

🚀 Java Revision Journey – Day 03 Continuing my Java revision, today I focused on Strings in Java, which play a major role in text processing and application development. 📌 Topics Covered: Strings ✔ Introduction to Java Strings ✔ Why Strings are Immutable ✔ String Concatenation ✔ Commonly Used String Methods String Handling Classes ✔ String Class ✔ StringBuffer Class ✔ StringBuilder Class ✔ Strings vs StringBuffer vs StringBuilder Understanding how Java handles strings helps in writing more efficient and optimized programs. Consistency in revisiting fundamentals helps build a stronger programming foundation. #Java #CoreJava #Programming #LearningJourney #BackendDevelopment #String #JavaDeveloper #Learning

✅ Java Features – Step 22: Java 8 → Java 17 Recap 🚀 Over the past few posts, I’ve been revisiting some key Java features introduced from Java 8 to Java 17. A quick recap of the highlights: 🔹 Java 8 Streams API Optional Functional Interfaces Lambda Expressions 🔹 Java 9–11 Factory methods (List.of, Set.of, Map.of) var for local variable type inference New String methods (isBlank, strip, repeat) Modern HttpClient API 🔹 Java 14–15 Switch expressions Text blocks 🔹 Java 16–17 Records Sealed classes Pattern matching for instanceof Key takeaway Java has evolved significantly to: Reduce boilerplate Improve readability Support modern programming patterns Understanding these features helps write cleaner and more maintainable backend code. Next up: Practical examples of modern Java features in real backend applications ⚙️

📘 1. TOP 15 CORE JAVA QUESTIONS (WITH SHORT ANSWERS) 🔥 Core Java (1–15) 1. What is JVM? → Runs Java bytecode 2. JDK vs JRE → Dev vs Runtime 3. == vs equals() → Reference vs Content 4. Why String immutable? → Security + caching 5. String pool? → Memory optimization 6. OOP principles → 4 pillars 7. Encapsulation → Data hiding 8. Inheritance → Code reuse 9. Polymorphism → Many forms 10. Abstraction → Hiding complexity 11. final vs finally vs finalize 12. Exception hierarchy 13. Checked vs unchecked 14. Multithreading → concurrency 15. Synchronization → thread safety # java #Code #Java #springboot

Day 40 – Advanced Java Strings & Input Handling ☕ Today I revised advanced concepts related to Strings and input handling in Java. Topics covered: 🔹 Inbuilt String methods 🔹 Converting String to character array 🔹 Mutable vs Immutable Strings 🔹 Difference between StringBuilder and StringBuffer 🔹 Handling input using nextLine() with integers and strings 🔹 Understanding buffer issues in input handling 🔹 Converting mutable to immutable and vice versa 🔹 Difference between split() and StringTokenizer Revisiting these concepts helped me better understand how Java handles strings internally and how input operations can sometimes lead to unexpected issues if not handled properly. Strengthening core concepts step by step 🚀 #Day40 #JavaJourney #Strings #CoreJava #ProgrammingFundamentals