Java program notes pdf, Study notes of Engineering

Download Java program notes pdf and more Study notes Engineering in PDF only on Docsity!

Comprehensive BCA Java Programming Notes Reporter ( : (——— Table of Contents», 03 | Exceptions 04 | Packages & Interfaces 05 | Collections Framework Inheritance & Polymorphism Class, Object, and Constructor Fundamentals O1 O2 O03 Defining Class and Object Constructor Types and Usage Method Overloading Basics A class is a blueprint for objects; an object Default and parameterized constructors Multiple methods with same name but is an instance with state (fields) and initialize objects. ‘public Car(String m) { different parameters. ‘void drive(int speed); behavior (methods). Example: “class Car { model =m; }* Ensures proper object setup void drive(int speed, String gear);’ Enables String model; void start() {} } Car myCar = on instantiation. flexible function calls. new Car();~ Inheritance Types Overview Hierarchical Inheritance Multiple subclasses extend one superclass. Example: “class Animal {} class Dog extends Animal {} class Cat extends Animal {} Promotes code reuse. Single and Multilevel Inheritance UML Diagrams for Inheritance Single: One subclass extends one superclass. Include class diagrams showing extends arrows: Multilevel: Chain like ABC. Code: ‘class Vehicle — Car, Vehicle — Bike. Visualize Vehicle {} class Car extends Vehicle {} class relationships f SportsCar extends Car { }* Q2 eritance & Polymorphis Types of Inheritance with Code Examples ingle, Multilevel, and Multiple Inheritance Single: Direct extension. Multilevel: Sequential. Multiple: Via interfaces. Code snippets demonstrate each with outputs. super and final Keywords “super()* calls parent constructor; ~ super.method()* parent method. ~ final” prevents inheritance/ overriding. Examples: “final class Immutable { }* Practical Code Traces Step-by-step: Constructor chaining with super. Output: Parent then child initialization logged. Abstract Classes vs Interfaces Comparison Table Methods Abstract + Concrete Abstract + Default Variables Instance vars Constants Inheritance Single Multiple Constructors Yes No Runtime vs Compile-Time Polymorphism Compile-Time (Overloading) Runtime (Overriding) 5 Exam-Level Programs Resolved at compile: Method Resolved at runtime via virtual Solved: Bank account signature matching. Example: ~ table. Dynamic dispatch polymorphism, vehicle fleet add(int a, int b)* vs ‘add(double example with Animal hierarchy. management. Include code, a, double b)*. outputs, UML. oO O e Exception Handling Basics try-catch-finally Structure “try { risky code } catch(Exception e) { handle } finally { cleanup }° Ensures resource release. Exception Hierarchy Diagram rf Throwable > Error/Exception. — Exception @ Checked/Runtime. ie Visual tree diagram. Multiple Catch Blocks / Specific first: “catch( ArithmeticException e) {} catch( Ce Exception e) {}* Handles hierarchy ), ees properly. throw vs throws and Custom Exceptions Py throw and throws Keywords “thraw new Exception("Msg");° Manual throw. “void method() throws IOException {}* Declaration. ‘class MyException extends Exception {}* Usage: Validate input, throw if invalid. Example code. PFA 4 Solved Programs Programs: Divide by zero handler, file read exceptions, custom age validator. Outputs traced. Creating Packages and Access Modifiers Access Modifiers Scope User-Defined Packages . . . public: All; protected: Subclass/package; package com.beajava;’ Compile: ‘Javac — gefauit: Package; private: Class only. Practical Examples Example 1: Package with classes using -d. java’. Import: “import com.bcajava.; = Table comparison. protected access across subclasses. Multiple Inheritance via Interfaces =) 2] Achieving Multiple Inheritance Interface Best Practices Class implements multiple interfaces. Constants, functional methods. “class MyClass implements 11, 12 [}* Example: Drawable + Resizable for Resolves diamond issue. shapes. 3 Practical Examples 1. Logger interface multiple imp. 2. Banking transactions. Code + outputs. ArrayList vs LinkedList Comparison ArrayList Characteristics LinkedList Features Doubly-linked, fast insert/delete O(1). Use for queues/stacks. Dynamic array, fast random access O(1). “List< String> list = new ArrayList<>(); list.add("Java"); ArrayList vs LinkedList Comparison Performance Table Operation ArrayList LinkedList Get(index) O(]) O(n) Insert O(n) O(1) Memory Less More sass