Beginner

 [USB Device]     |    v [USB Port on Computer]    |    v [Data Transfer] - High-speed data transfer between device and computer.    |    v [Power Supply] - Provides power to charge devices or power peripherals.    |    v [Hot Swapping] - Connect/disconnect devices without turning off the computer.    |    v [Plug-and-Play] - Automatic detection and driver installation.    |    v [Universal Compatibility] - Works with various devices and older USB versions.    |    v [Multiple Device Support] - Hubs allow connecting multiple devices.    |    v [Data Synchronization] - Transfer files and sync data.

Search Engine: Web pages ko index karta hai aur search queries ke basis pe results generate karta hai. Browser: Search engine ke hyperlinks ko display karta hai, aur user clicks karne par relevant web page ko load karta hai.  ### **Search Engine Features:** - **Crawling:**    - Web pages ko automatically visit karke unka content gather karna. - **Indexing:**    - Web pages ke content, metadata, aur keywords ko structured format mein store karna. - **Query Processing:**   - User queries ko analyze karna aur relevant indexed pages ko retrieve karna. - **Ranking:**    - Retrieved pages ko relevance aur quality ke basis pe rank karna. - **Search Results:**    - Search queries ke basis pe results generate karna jisme text snippets, images, and links included hote hain. - **Autocomplete:**    - Search suggestions provide karna jab user query type karta hai. - **Personalization:**    - User’s search history aur preferences k...

Let's break it down into simpler terms and use examples to illustrate each type of server. ### What is a Server? A **server** is a powerful computer or software that provides resources, data, services, or programs to other computers, called **clients**, over a network. Think of a server as a helper or provider that clients can ask for information or services. ### Types of Servers with Examples 1. **Web Server**:    - **Purpose**: Delivers web pages to your browser when you visit a website.    - **Example**: When you type `www.example.com` in your browser, a web server (like Apache or Nginx) sends the web page to your browser.     2. **Database Server**:    - **Purpose**: Stores and manages data in a structured way and allows you to retrieve and manipulate this data.    - **Example**: When you use an app like Facebook, the database server stores all your profile information, posts, and...

 ### DBMS (Database Management System) A **Database Management System (DBMS)** is software that interacts with the user, applications, and the database itself to capture and analyze data. A DBMS allows users to create, read, update, and delete data in a database. It ensures data integrity, security, and concurrency while providing support for data manipulation and retrieval. #### Types of DBMS 1. **Hierarchical DBMS**:    - Data is organized in a tree-like structure.    - Example: IBM Information Management System (IMS). 2. **Network DBMS**:    - Data is organized in a graph, allowing many-to-many relationships.    - Example: Integrated Data Store (IDS). 3. **Relational DBMS (RDBMS)**:    - Data is stored in tables (relations) and can be linked based on data common to each.    - Examples: MySQL, PostgreSQL, Oracle, Microsoft SQL Server. 4. **Object-oriented DBMS (OODBMS)**:    - Data is stored in objects, similar...

Listing methods for each class in `java.awt.event.*`, `java.awt.*`, and `javax.swing.*` comprehensively would be extensive here. Instead, I'll outline a representative set of methods for some key classes across these packages to give you a sense of their functionalities. ### `java.awt.event.*` Here are example methods from some key classes in `java.awt.event.*`: 1. **`ActionEvent`**:    - `getActionCommand()`    - `getModifiers()`    - `getSource()` 2. **`ActionListener`** (Functional Interface):    - `void actionPerformed(ActionEvent e)` 3. **`MouseEvent`**:    - `getX()`    - `getY()`    - `getButton()`    - `getClickCount()` 4. **`MouseListener`**:    - `void mouseClicked(MouseEvent e)`    - `void mousePressed(MouseEvent e)`    - `void mouseReleased(MouseEvent e)` 5. **`KeyListener`**:    - `void keyTyped(KeyEvent e)`    - `void keyPressed(KeyEvent e)` ...

### `java.awt.event.*` Classes and Interfaces 1. **Classes**:    - `ActionEvent`: Represents an action event triggered by a user action, such as clicking a button.    - `AdjustmentEvent`: Indicates a change in an adjustable component, like a scrollbar.    - `ComponentEvent`: Signals changes in a component's state, such as visibility or size.    - `FocusEvent`: Indicates changes in component focus, like gaining or losing focus.    - `InputEvent`: Represents events from keyboard and mouse input.    - `ItemEvent`: Indicates changes in state of items, like selections in a list or checkbox.    - `KeyEvent`: Represents key events generated by keyboard input.    - `MouseEvent`: Indicates mouse events, such as clicks, movements, and drags.    - `MouseWheelEvent`: Represents mouse wheel movement events.    - `TextEvent`: Indicates changes in text components, such as typing or pasting text.   ...

-  Swing is Adv version of AWT ### 1. `java.lang.Object` - **Role:** Root class for all Java classes. Every class in Java is a direct or indirect subclass of `Object`. - **Key Methods:** Provides fundamental methods like `equals()`, `hashCode()`, `toString()`, and `getClass()`. - **Usage:** Used as a base for all Java objects and provides basic functionalities. ### 2. `java.awt.Component` - **Role:** A subclass of `Object`, `Component` is an abstract class that serves as the base for all UI components in AWT (Abstract Window Toolkit). - **Key Methods:** Defines methods for rendering, event handling (`addMouseListener()`, `addKeyListener()`), and component lifecycle (`setVisible()`, `setEnabled()`). - **Usage:** Provides the foundation for UI components like buttons, text fields, and panels in Java GUI applications using AWT. ### 3. `java.awt.Container` - **Role:** Extends `Component` and serves as a base class for components that can contain other AWT components. - **Key Methods:**...

 In Java, the Stream API, introduced in Java 8, is a powerful and flexible way to process sequences of elements. It provides a high-level abstraction for operations on collections of data. A stream is not a data structure; instead, it takes input from collections, arrays, or I/O channels. Streams can be used to perform operations like filtering, mapping, and reducing on collections of data in a more declarative and functional style. ### Key Features of Streams 1. **Declarative**: Streams allow you to write code that describes what you want to achieve, rather than how to achieve it. 2. **Composability**: Streams support operations that can be combined to form complex data processing pipelines. 3. **Parallelism**: Streams can be processed in parallel, making it easier to leverage multi-core processors. 4. **Laziness**: Streams are lazy and do not perform any computations until they are explicitly needed. This allows for more efficient processing. ### Stream Operations Stream operatio...

// ForEach method is method of Iterable Interface // It takes parameter as Consumer Functional Interface // it is Functional Interface i.e. void accept(Type obj) has the only method // nums.forEach(Consume obj) forEach values provide krta hai // Consumer oos values ke sath kya krna hai woh krta hai   // n-> System.out.println(n) all automaticallt is inside the anonymous class of method void accept(Integer)         // automatically creates object of anonumous class who implements Consumer interface         // it automaticaly Detects n is type of Integer         // There we used Lambda Expression          // Simply forEach method gives values to Consumer object 'n' and it does operations like print of anything --------------------------------------------------------------------------------------------------------------------------- ### Detailed Explanation 1. **Lambda Expression**:    ``...

Comparator vs Comparable * Comparator    - Its Interface and Functional Interface   - Its an Functional Interface it means we can use anonymous Inner class and Lambda Expressions   - Comparator has non abstract method which is " int compare(int , int) "   - It take 2 Type class Objects (Ex: int compare(Integer i , Integer j))   - All Wrapper Classes has " .compare(type , type) " method which returns int value    - if returns positive integer it means swap if negative it means no swap if zero it means both are equal   - Comparator is as a third person who are comparing objects and generates logic   - But Collections.sort(Type , comparator obj ) ye sort krta hai according Comparator (compare(T,T)) * Comparable   - Comparable is Normal Interface   - It has method name " int compareTo(Type object) "    - There are 2 types of compareTo(Type obj) and compareTo(String obj)   - (1) - compareTo(Type obj) it just gives cla...

 `compareTo` method ke do alag-alag signatures hote hain, ek jo `Object` type ko leta hai aur ek jo `String` type ko leta hai. Yeh do alag methods hote hain jo alag context mein use hote hain: ### `compareTo` Method with `Object` Parameter 1. **Signature:**    - `int compareTo(Object o)`    - Yeh method `java.lang.Comparable` interface mein define hota hai. Iska use generally objects ke comparison ke liye hota hai, jab ek object ko dusre object ke saath compare karna hota hai. 2. **Example:**    - Example mein, agar aap `Comparable` interface implement karte hain ek custom class mein, to `compareTo` method ek `Object` parameter leta hai:    ```java    public class MyClass implements Comparable<MyClass> {        private int value;        public MyClass(int value) {            this.value = value;        }        @Overrid...

 The Collections class in Java provides utility methods for working with collections, such as List , Set , and Map . It offers various static methods to perform common operations like sorting, searching, and synchronizing collections. Here are some key functionalities provided by the Collections class: Sorting Collections: sort(List<T> list) : Sorts the specified list into ascending order. sort(List<T> list, Comparator<? super T> c) : Sorts the specified list according to the order induced by the specified comparator. Searching Collections: binarySearch(List<? extends Comparable<? super T>> list, T key) : Searches the specified list for the specified object using the binary search algorithm. binarySearch(List<? extends T> list, T key, Comparator<? super T> c) : Searches the specified list for the specified object using the binary search algorithm. Synchronization of Collections: synchronizedList(List<T> list) : Returns a synchronize...

jab `ref1.run()` aur `ref2.run()` ko directly call karte ho, tab wo methods main thread mein sequentially execute hote hain, alag-alag threads mein nahi. Iska matlab hai ki aap actual multithreading nahi kar rahe ho.  *  Thread class has only the way we can achieve multithreading *  We can Create Thread using Thread class and Runnable Interface * Thread class has many method :  * join() -> it will wait for completion of Thread * sleep(milisec) -> it will wait after statment for given miliseconds * Runnable is the FunctionalInterface it means we can use Anonymous inner class and Lambda                    Expressions (only one non - abstract method is there which is run())  ***Multithreading only possible using start() method of Thread class Java mein true multithreading achieve karne ke liye, aapko `Thread` class ka use karke `Runnable` instances ko alag threads mein start karna padta hai. Main differen...

 Jab aap `a + b` jaisa simple program run karte hain aur uska result (answer) aata hai, to is process ko CPU aur operating system (OS) ke coordination mein execute hota hai. Chaliye is process ko detail mein samajhte hain: ### Step-by-Step Execution: 1. **Program Load (प्रोग्राम लोड)**:    - Jab aap apne program ko run karte hain, operating system (OS) executable file ko memory (RAM) me load karta hai.    - Memory me program load hone ke baad, CPU ko instruction milte hain ki kya karna hai. 2. **CPU Execution (CPU क्रियान्वयन)**:    - CPU (Central Processing Unit) instruction set architecture (ISA) ke according instructions ko execute karta hai.    - `a + b` expression ko evaluate karne ke liye CPU arithmetic logic unit (ALU) use karta hai.    - ALU addition operation perform karta hai jisme `a` aur `b` ke values add hote hain. 3. **Result Generation (परिणाम उत्पन्न)**:    - CPU ALU `a + b` ko execute karne ke baad, result...

simpler way to understand `BufferedReader` as a resource: ### What is `BufferedReader`? `BufferedReader` is a tool in Java that helps read text from sources like files or keyboard input efficiently. It's like a helper that manages how data is fetched from these sources to your program. ### Why is it a Resource? It's called a resource because: - **Efficient Reading**: It reads chunks of text at once, which is faster than reading character by character. - **Uses System Resources**: It needs memory and system connections to do its job (like opening files or connecting to input streams). ### How to Use it Safely? When you're done using `BufferedReader`, you should: - **Close it**: This releases the memory and connections it used. If you forget, it can waste resources or cause errors. ### Example: ```java import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; public class BufferedReaderExample {     public static void main(String[] args) {   ...

 Let's break down what synthetic methods, method handles, and `invokedynamic` mean in the context of Java, especially in relation to lambda expressions and anonymous classes. ### Synthetic Methods A **synthetic method** in Java is a method that is generated by the compiler rather than being explicitly declared in the source code. These methods are typically used for internal purposes, such as: - **Lambda Expressions**: When you write a lambda expression, the Java compiler generates a synthetic method to implement the lambda's behavior. This method is not directly visible in your code but exists in the bytecode.    - **Inner Classes**: For inner classes, the compiler can generate synthetic methods to handle access to private members of the enclosing class. Synthetic methods have specific naming conventions that include `$lambda` for lambda expressions or `$1`, `$2`, etc., for anonymous classes or inner classes. ### Method Handles A **method handle** in Java is a typed refe...

// method 2 where lambda expression use there is no anonymous inner class // just creating diff references to perform diff operations // (diff objects are creating and implementing in objects) important points: * @FunctionalInterface it only takes 1 method * lambda exressions work only when there is @FunctionalInterface * (->) using this lambda expression can be used * see example below , * the key point is that methods from Object (like toString , hashCode , and equals )    do not affect the functional interface rules because they are considered to be present in all interfaces implicitly. The interface Ex is still a valid functional interface with the @FunctionalInterface annotation because it only has one abstract method, void code() . *********************************************************************************** @FunctionalInterface // It means it only takes 1 method interface Ex {     void code(); } class A implements Ex {     public vo...

 ### Wrapper Classes in Java Wrapper classes in Java provide a way to use primitive data types (int, char, etc.) as objects. Each primitive data type has a corresponding wrapper class in the `java.lang` package: | Primitive Type | Wrapper Class  | | -------------- | -------------- | | `byte`         | `Byte`         | | `short`        | `Short`        | | `int`          | `Integer`      | | `long`         | `Long`         | | `float`        | `Float`        | | `double`       | `Double`       | | `char`         | `Character`    | | `boolean`      | `Boolean`      | ### Key Features of Wrapper Classes 1. **Autoboxing and Unboxing**:     - **A...