Java Custom Exceptions & Error Handling

🚀 Starting My Java Learning Journey – Day 13 ♦Topic: Exception Handling in Java Exception Handling is used to handle runtime errors so that the program does not crash abruptly. It helps in maintaining the normal flow of the program. ✅ Types of Exceptions 1)Checked Exceptions → Checked at compile time 2) Unchecked Exceptions → Occur at runtime ✅ Keywords Used in Exception Handling ✔ try → block where code is written ✔ catch → handles the exception ✔ finally → always executes (optional) ✔ throw → used to explicitly throw an exception ✔ throws → declares exceptions ✅ Example Program public class Main { public static void main(String[] args) { try { int result = 10 / 0; // may cause exception System.out.println(result); } catch (ArithmeticException e) { System.out.println("Cannot divide by zero"); } finally { System.out.println("Execution completed"); } } } Output: Cannot divide by zero Execution completed 💡 Key Points: ✔ Prevents program crash ✔ Helps handle runtime errors ✔ Improves program reliability #Java #JavaLearning #Programming #BackendDevelopment #CodingJourney #ExceptionHandling

Continuing my Java learning journey by understanding Exception Handling, an essential concept for building robust and reliable applications. In Java, an exception is an event that occurs during program execution which disrupts the normal flow of the program. Exception Handling is used to handle such situations gracefully without crashing the application. Java provides a structured way to manage errors using keywords like: try catch finally throw throws 🔷 💡 Why Exception Handling is Important? Prevents program crashes Handles runtime errors smoothly Maintains normal flow of execution Improves application reliability Helps in debugging and error tracking 🔷 💡 Types of Exceptions 1️⃣ Checked Exceptions Checked at compile time Must be handled explicitly Example: File handling errors 2️⃣ Unchecked Exceptions Occur at runtime Caused by logical errors Example: Arithmetic errors, Null pointer 🔷 💡 Key Concepts try → block where risky code is written catch → handles the exception finally → always executes (cleanup code) throw → used to explicitly throw an exception throws → declares exceptions in method signature Real-World Importance📌 Exception Handling is widely used in backend systems to: Handle API failures Manage database errorsValidate user input Ensure smooth user experience Without proper exception handling, applications may crash or behave unpredictably. Understanding this concept is essential before moving into advanced topics like Multithreading, JDBC, and Spring Boot, where error handling plays a critical role. #Java #ExceptionHandling #JavaDeveloper #ProgrammingConcepts #BackendDevelopment #FullStackJourney #LearningConsistency

Mastering Java methods, constructors, and overloading is key to writing clean, flexible code. 🚀 These fundamentals help you reuse logic, initialize objects, and handle multiple inputs efficiently. https://lnkd.in/d9uvNnJP #Java #OOP #Programming

🚀 Introduction to ArrayList in Java As part of strengthening my Java fundamentals, I explored one of the most commonly used data structures — ArrayList from the Java Collections Framework. 🔹 What is ArrayList? ArrayList is a dynamic array that can grow and shrink in size, making it more flexible than traditional arrays. 🔹 Key Properties of ArrayList ✔️ Stores heterogeneous data (different data types using Object type) ✔️ Default initial capacity is 10 ✔️ Maintains the order of insertion ✔️ Duplicates are allowed ✔️ Can store null values ✔️ Resizing is a costly operation (involves creating a new array and copying elements) ✔️ Supports dynamic memory allocation 🔹 Constructors in ArrayList 1️⃣ Zero Parameter Constructor ArrayList list = new ArrayList(); 2️⃣ Single Parameter Constructor (Capacity) ArrayList list = new ArrayList(20); 3️⃣ Collection-Based Constructor ArrayList list = new ArrayList(existingCollection); 🔹 Hierarchy of ArrayList in Java 📌 Java Hierarchy: Iterable → Collection → List → ArrayList 👉 ArrayList implements the List interface and is part of the java.util package. 💡 Key Takeaway: ArrayList is a powerful and flexible data structure widely used in Java applications. Understanding its properties and internal behavior helps in writing efficient and optimized code. Keep learning, keep building, and keep growing 💻🚀 #Java #ArrayList #CollectionsFramework #Programming #Developers #LearningJourney #KeepGrowing TAP Academy

📘 Day 34 – Java Concepts: Access Modifiers & Method Overriding Today I revised some important Java concepts that help in writing secure and flexible code. 🔹 Access Modifiers in Java Access modifiers define the visibility of classes, methods, and variables. • public – Accessible from anywhere • protected – Accessible within the same package and subclasses • default – Accessible only within the same package • private – Accessible only within the same class 📊 Accessibility (Summary): ✔ Inside class → All accessible ✔ Same package → public, protected, default ✔ Subclass (different package) → public, protected ✔ Outside package → only public 🔹 Rules of Method Overriding • Method name must be the same • Parameters must be the same • Return type must be same or covariant • Access modifier cannot be more restrictive 🔹 Covariant Return Type A child class method can return a subtype of the parent method’s return type. 🔹 Final Keyword • final variable → constant • final method → cannot be overridden • final class → cannot be inherited 💡 Understanding these concepts improves code reusability, security, and maintainability. #Java #OOP #Programming #CodingJourney #Day34 #Developers

Day 38 at #TapAcademy 🚀 ArrayList in Java – A Must-Know for Every Developer When working with Java, one of the most commonly used data structures is ArrayList — a powerful and flexible part of the Java Collection Framework. 🔹 What is ArrayList? ArrayList is a resizable array implementation of the List interface. Unlike traditional arrays, it can grow or shrink dynamically as elements are added or removed. 🔹 Why use ArrayList? ✔ Dynamic size (no need to define length in advance) ✔ Allows duplicate elements ✔ Maintains insertion order ✔ Provides fast access using index ✔ Comes with rich built-in methods 🔹 Common Methods: 📌 add(E e) – Add element 📌 get(int index) – Access element 📌 set(int index, E e) – Update element 📌 remove(int index) – Delete element 📌 size() – Get number of elements 🔹 Constructors: 📌 ArrayList() – Creates an empty list 📌 ArrayList(int initialCapacity) – Sets initial size 📌 ArrayList(Collection<? extends E> c) – Creates list from another collection 💡 Example: ArrayList<String> names = new ArrayList<>(); names.add("Alice"); names.add("Bob"); names.add("Charlie"); System.out.println(names); 🔹 Difference: Arrays vs ArrayList 📌 Arrays ▪ Fixed size (cannot grow/shrink) ▪ Can store primitives (int, char, etc.) ▪ No built-in methods (limited operations) ▪ Faster for basic operations 📌 ArrayList ▪ Dynamic size (resizable) ▪ Stores only objects (wrapper classes like Integer) ▪ Rich built-in methods (add, remove, etc.) ▪ More flexible and easy to use 📈 Understanding ArrayList is essential for writing efficient, clean, and scalable Java programs—whether you're preparing for interviews or building real-world applications. #Java #ArrayList #Programming #Coding #DataStructures #JavaDeveloper #Learning #Tech #TapAcademy

🚀 Mastering Java Switch Statements – From Basic to Advanced I recently practiced different ways of using switch statements in Java, and here’s what I learned step-by-step 👇 🔹 1. Traditional Switch (Basic) ➡️ Used multiple case blocks with break statements ➡️ Works but repetitive and lengthy 🔹 2. Grouping Cases ➡️ Combined multiple cases using commas ➡️ Cleaner and reduces duplication 🔹 3. Switch with Arrow (->) ➡️ Introduced modern syntax ➡️ No need for break ➡️ More readable and concise 🔹 4. Using Variable for Output ➡️ Stored result in a variable ➡️ Better for structured and reusable code 🔹 5. Switch as Expression ➡️ Directly returns value ➡️ Makes code shorter and powerful 🔹 6. Using yield Keyword ➡️ Used in block-style switch expressions ➡️ Helps return values explicitly ➡️ Converted output to uppercase for better formatting ✨ Key Takeaways: ✔ Code readability improved step by step ✔ Reduced redundancy ✔ Learned modern Java features ✔ Understood difference between statement vs expression 🙏 Grateful for the Guidance: A special thanks to my mentor Anand Kumar Buddarapu sir for guiding me and encouraging me to explore Java pattern programming and logical coding techniques. Saketh Kallepu Uppugundla Sairam #Java #Programming #CodingJourney #JavaDeveloper #Learning #SwitchCase #CleanCode #TechSkills #Developers #StudentDeveloper

🚀 Why Runnable is Preferred Over Thread in Java? Many beginners start with extending the Thread class, but in real-world development, Runnable (or lambda) is the preferred approach. Let’s understand why 👇 🔹 Problem with Thread Class Java supports single inheritance. 👉 If you write: class A extends Thread ❌ You cannot extend any other class 🔹 Real-Time Scenario class A extends B 👉 Now you want threading also… ❌ You CANNOT do: class A extends B, Thread // Not possible 🔹 Solution: Use Runnable(Functional Interface)✅ class A extends B implements Runnable { public void run() { System.out.println("Running"); } } 👉 Now you can: ✔ Extend another class ✔ Use threading ✔ Follow clean design 🔹 Why Runnable is Better? ✔ Supports flexibility ✔ Follows good design (separates task & thread) ✔ Works with modern APIs (ExecutorService, ThreadPool) ✔ Supports lambda expressions 🎯 Key Takeaway 👉 “Since Java supports single inheritance, we use Runnable instead of extending Thread to achieve better flexibility and design.” #Java #Multithreading #JavaDeveloper #Coding #SoftwareEngineering #Learning

While learning Java, I realized something important: 👉 Writing code is easy 👉 Handling failures correctly is what makes you a good developer So here’s my structured understanding of Exception Handling in Java 👇Java Exception Handling — the part most tutorials rush through. If you're writing Java and your only strategy is wrapping everything in a try-catch(Exception e) and hoping for the best, this is for you. A few things worth understanding properly: 1. Checked vs Unchecked isn't just trivia Checked exceptions (IOException, SQLException) are compile-time enforced — the language is telling you these failure modes are expected and you must plan for them. Unchecked exceptions (RuntimeException and its subclasses) signal programming bugs — they shouldn't be caught and hidden, they should be fixed. 2. finally is a contract, not a suggestion That block runs regardless of what happens. Use it for resource cleanup. Better yet, use try-with-resources in modern Java — it handles it automatically. 3. Rethrowing vs Ducking "Ducking" means declaring throws on a method and letting the caller deal with it. Rethrowing means catching it, maybe wrapping it with more context, and throwing again. Know when each makes sense. 4. Custom exceptions add clarity A PaymentDeclinedException tells the next developer (and your logs) far more than a generic RuntimeException with a message string. The image attached gives a clean visual overview — bookmarking it might save you a Google search or two. TAP Academy kshitij kenganavar What's your go-to rule for exception handling in production systems? #Java #SoftwareDevelopment #CleanCode #JavaDeveloper #BackendEngineering #TechEducation #100DaysOfCode

🚀 Day 3 of My Java Learning Journey – Control Statements in Java Today, I learned how programs make decisions and repeat tasks using Control Statements in Java. These are essential for building logic in real-world applications. 🔹 Types of Control Statements: ➤ 1. if-else Statement Used for decision making 👉 Executes code based on conditions if (x > 10) { System.out.println("Greater than 10"); } else { System.out.println("Less than or equal to 10"); } ➤ 2. switch Statement Used when we have multiple choices 👉 Cleaner alternative to multiple if-else switch(day) { case 1: System.out.println("Monday"); break; case 2: System.out.println("Tuesday"); break; default: System.out.println("Invalid day"); } ➤ 3. Loops (Repetition Statements) Used to execute code multiple times ✔ for loop – when number of iterations is known ✔ while loop – when condition is checked before execution ✔ do-while loop – executes at least once for(int i = 1; i <= 5; i++) { System.out.println(i); } 💡 Key Learning: Control statements help in decision-making and repeating tasks, making programs smarter and more dynamic. 📌 Practiced writing programs using if-else, switch, and loops to strengthen my logic-building skills. #Java #Programming #CodingJourney #LearningJava #ControlStatements #100DaysOfCode #Developers 🚀