/JavaDevCrashCourse

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Java Development Crash Course

Certificate

Section 1: Core Java

Section 2: Maven

Maven Introduction:

  • Introduction to Maven:
    • Maven is a project management tool.
    • It is essential beyond syntax and concepts when building a project.
  • Project Building Steps:
    • Compilation of files.
    • Running files.
    • Testing files.
    • Creating a package.
    • Deployment.
  • External Libraries and Dependencies:
    • Projects often require external libraries.
    • Examples include connectors for database interaction (e.g., MySQL Connector for MySQL, Postgres Connector for Postgres).
    • Introduction to Hibernate as a tool for saving data in a database without SQL queries.
  • Library Retrieval in Java:
    • Libraries are obtained as JAR files.
    • Process involves searching and downloading from the internet.
    • Different IDEs support adding JAR files to the project.
  • Transitive Dependencies in Hibernate:
    • Hibernate requires multiple JAR files due to transitive dependencies.
    • Upgrading dependencies in the future may require redownloading.
  • Compatibility and Versioning:
    • Different frameworks may have their own dependencies.
    • Version compatibility between frameworks is crucial.
    • Matching versions ensures proper collaboration between frameworks.
  • Challenges with Manual Dependency Management:
    • Time-consuming process.
    • Potential issues when sharing projects with colleagues.
    • Synchronization of versions is critical.
  • Introduction to Maven as a Solution:
    • Maven streamlines the process of managing dependencies.
    • Automates the retrieval of dependencies.
    • Helps maintain version compatibility.
  • Other Project Management Tools:
    • Mention of other tools like Gradle and Ivy.
    • Selection of Maven for its beginner-friendly nature.
  • Focus on Dependency Management:
    • Emphasis on understanding Maven for handling dependencies.
    • Mention of Maven plugins for various project phases (compiling, testing, running), but the focus in this section is on dependencies.

Maven in IDE

  • Project Collaboration with Maven:
    • Emphasizes the collaborative aspect of Maven, where project configurations and dependencies are easily shared among team members.
    • The video concludes with a teaser for the next video, where the workings behind the scenes will be explained.
  • Maven Installation:
    • Maven can be installed locally on the machine and accessed through the command line.
    • IDEs, such as Eclipse or IntelliJ, also support Maven.
  • Getting Maven from Official Website:
    • Visit the official Maven website: Maven Apache.
    • Download Maven from the website and set the path for command line usage.
  • Using Maven with IDEs:
    • IntelliJ and Eclipse provide Maven support.
    • Create a new project and choose Maven as the build system to ensure consistency in project structure.
    • Project structure remains the same regardless of the IDE used.
  • Project Creation in IntelliJ:
    • Create a new project in IntelliJ.
    • Specify project name (e.g., Maven Demo), language (Java), and choose Maven as the build system.
    • Default project structure is established.
  • Maven Plugins in IDEs:
    • Maven plugins facilitate various stages of project development.
    • In IntelliJ, the Maven option is typically found in the top right.
    • The project life cycle includes compilation, testing, packaging, installing, and deploying.
  • Maven Life Cycle Options in IDE:
    • Life cycle options include compile, test, package, install, and deploy.
    • Maven automates these processes, reducing manual effort.
    • Example: Clicking "compile" initiates Maven to compile the project.
  • Maven Plugins and Features:
    • Maven provides plugins to achieve different tasks in the development life cycle.
    • Plugins assist in compiling, testing, packaging, installing, and deploying the project.
  • Maven Archetype:
    • Maven has an archetype feature.
    • Further details about Maven archetypes and plugins are discussed in upcoming videos.
  • Simplifying Project Tasks with Maven:
    • Demonstrates how Maven simplifies tasks like compilation, testing, packaging, installation, and deployment.
    • Emphasizes the convenience of using IDE features for these tasks.
    • Introduction to Maven plugins that automate these tasks.

Getting Dependencies:

  • Introduction to Archetypes:
    • Maven provides archetypes, which are templating tools for project setup.
    • Archetypes simplify the process of creating project configurations and dependencies.
  • Usage of Archetypes:
    • Archetypes are useful for building specific types of projects, such as web projects.
    • They provide pre-configured templates that can be customized or used as is.
  • Creating Project Templates:
    • Archetypes allow users to create their own templates for specific project types.
    • Templates can include configurations and dependencies for consistent project setups.
  • Dependency Handling in Maven:
    • Maven helps in managing project dependencies, specifically JAR files.
    • The process involves searching for libraries online, downloading them, and adding them to the project.
  • Dependency Search and Download:
    • Demonstrates how to search for a library, e.g., MySQL Connector, online.
    • Shows the manual process of downloading and adding the JAR file to the project.
  • Repository Usage in Maven:
    • Introduces the Maven Repository (repository.com) as an alternative to manual downloads.
    • Shows how to search for and download a library using Maven dependency syntax.
  • Understanding Maven's POM.xml:
    • Focuses on the POM.xml file (Project Object Model) in Maven.
    • Explains the significance of group ID, artifact ID, and version in identifying and managing dependencies.
  • Group ID in Maven:
    • Group ID ensures uniqueness for a library throughout the world.
    • It is often derived from the organization's domain name, ensuring global uniqueness.
  • Artifact ID in Maven:
    • Artifact ID is the project name.
    • Used in combination with the group ID and version to uniquely identify the library.
  • Dependency Management in POM.xml:
    • Demonstrates how to add dependencies to the POM.xml file.
    • Every library is specified with group ID, artifact ID, and version.
  • Refreshing Maven Project in IDE:
    • Shows how to refresh or reload a Maven project in the IDE after updating the POM.xml file.
    • Maven automatically downloads and adds the specified dependencies.
  • Transitive Dependencies:
    • Introduces the concept of transitive dependencies.
    • Explains that a library may have dependencies of its own, known as transitive dependencies.
  • Adding Multiple Dependencies:
    • Demonstrates adding multiple dependencies, such as MySQL Connector and Hibernate, to the POM.xml.
    • After saving and reloading, Maven downloads and adds all required JAR files.
  • Sharing Projects with Dependencies:
    • Highlights the convenience of sharing projects by sharing the POM.xml file.
    • Recipients can reload Maven, and the IDE will automatically download and manage dependencies.

Effective POM:

  • POM File Configuration:
    • The pom.xml file is crucial for Maven configuration.
    • Configuration involves specifying group ID, artifact ID, and version for creating JAR files or libraries.
    • Dependencies for the project are also mentioned in the dependencies tag.
    • Dependencies can include transitive dependencies.
  • Working with Plugins:
    • Plugins can be added to the pom.xml file for additional functionality.
    • A separate plugins tag allows the configuration of various plugins.
  • Effective POM:
    • The concept of the effective POM or super POM is introduced.
    • Maven looks at the effective POM when working with a project.
    • Changes made in the pom.xml file are reflected in the effective POM.
  • Viewing Effective POM in IntelliJ:
    • In IntelliJ, right-click on pom.xml.
    • Navigate to the "Maven" option and choose "Show Effective POM."
    • The effective POM includes more settings than those explicitly added in the pom.xml file.
  • Default Plugins in Effective POM:
    • The effective POM includes default plugins even if not explicitly added.
    • Examples of default plugins include Auto Run, clean, resources, Jar, package, and compiler.
  • Understanding Effective POM:
    • Changes made in the pom.xml file result in the creation of an effective POM.
    • Developers should focus on modifying the pom.xml file rather than directly altering the effective POM.
    • Effective POM provides a comprehensive view of the project configuration, including default settings and plugins.
  • Different IDEs and Effective POM:
    • Various IDEs may have different methods of displaying the effective POM.
    • A demonstration in IntelliJ is provided, and a future demonstration in Eclipse will be shown.
  • Importance of POM.xml:
    • The pom.xml file is the primary configuration file for Maven projects.
    • Developers specify project details, dependencies, and plugins in the pom.xml.
    • Maven uses the effective POM, created from the pom.xml, when executing tasks for the project.

Maven Archetype:

  • Archetypes in Maven:
    • Archetypes are templates in Maven that can be used to create project structures with predefined configurations.
    • Developers can use existing archetypes or create custom ones.
    • Archetypes simplify project setup by providing predefined configurations for specific frameworks or project types.
  • Creating a New Project with Archetypes:
    • To create a new project using archetypes, navigate to the new project creation option.
    • Choose the Maven archetype option and provide a name for the project (e.g., "Demo Spring project").
    • Select an archetype based on the type of project you want to create (e.g., J2EE, Quickstart, Web App).
    • Archetypes provide predefined configurations for common project types.
  • Archetype Catalogs:
    • Maven has an internal catalog of archetypes that comes with the Maven installation.
    • External catalogs, such as Maven Central, can be accessed to get a wider range of archetypes.
    • Maven Central provides numerous archetypes from the internet, expanding the available options.
  • Downloading Dependencies:
    • When an archetype is selected, Maven downloads the necessary dependencies and sets up the project structure.
    • Dependencies may include frameworks, libraries, and configurations required for the selected archetype.
    • Downloading from the internet may take some time as it fetches the required resources.
  • Example: Spring Boot MVC Archetype:
    • Demonstrates selecting a Spring Boot MVC archetype from Maven Central.
    • The selected archetype provides a default project structure and configurations for a Spring Boot MVC application.
    • Dependencies for Spring Boot Starter, Web MVC, Jersey, Jdbc, and H2 are automatically added to the project.
  • Advantages of Using Archetypes:
    • Archetypes save time and effort by providing ready-made project structures.
    • Developers don't have to manually configure dependencies or project settings.
    • Archetypes are especially useful for projects involving popular frameworks like Spring Boot.
  • Usage in Eclipse:
    • Similar options for choosing archetypes are available in Eclipse when creating a Maven project.
    • Developers can select archetypes during the initial project setup process in Eclipse.
  • Simplified Project Setup:
    • Archetypes abstract away the complexity of setting up a project from scratch.
    • They enable developers to start with a predefined structure and configurations, making the project setup process more efficient.

How Maven Works:

  • Maven Dependency Resolution:
    • Maven resolves dependencies for projects based on the information provided in the pom.xml file.
    • When a project specifies dependencies, Maven searches for them in the local machine first.
  • Local Repository (M2 Folder):
    • Each machine with Maven installed has a local repository known as the M2 folder.
    • The local repository stores copies of dependencies that have been downloaded previously.
  • Dependency Search Process:
    • Maven checks the local repository first for the requested dependencies.
    • If the dependencies are found locally, Maven uses the local copies, avoiding the need to download from the internet.
  • Maven Central Repository:
    • If a dependency is not found in the local repository, Maven then looks for it in the remote repository, typically Maven Central.
    • Maven Central is a central repository on the internet that hosts a vast collection of libraries and dependencies.
  • Dependency Update and Vulnerabilities:
    • Dependencies fetched from remote repositories may have vulnerabilities.
    • Maven may warn about vulnerable versions, and developers are encouraged to update to secure versions.
  • Security Measures and Company Repository:
    • Companies often prioritize security and may have an additional layer between Maven and the remote repository.
    • Company-wide repositories are maintained, containing only well-tested and secure libraries.
    • Maven first checks the local repository, then the company repository before attempting to download from the internet.
  • Version Issues and Resolution:
    • If there are issues with versions or dependencies not working as expected, developers can go to the local repository (M2 folder) and delete the specific file causing problems.
    • Deleting the file prompts Maven to download the dependency again, potentially resolving version or compatibility issues.
  • Best Practices:
    • Developers should ensure the security of dependencies, considering vulnerabilities and updates.
    • Companies may implement measures to verify and manage dependencies before they are added to the project.
  • Conclusion:
    • Understanding Maven's dependency resolution process can help developers troubleshoot issues related to dependencies.
    • It's essential to prioritize security and follow best practices when working with external libraries and dependencies.

Section 3: JDBC

JDBC Introduction

  • Introduction to JDBC:
    • Stands for Java Database Connectivity.
    • In the software industry, data interaction is crucial, and applications are built to store, fetch, and update data.
    • Initial data handling involves storing data in variables, but this is temporary, and data is lost when the application is closed.
  • Permanent Data Storage:
    • Need arises to store data permanently.
    • Storing data in a plain text (TXT) file is an option but is limited in terms of searchability and relational structure.
  • Relational Database Management System (RDBMS):
    • RDBMS allows data storage in a tabular format.
    • Provides a structured way to store and manage data permanently.
  • SQL (Structured Query Language):
    • SQL is used to interact with databases.
    • Learning SQL may not be practical for regular users or clients.
  • Database Connectivity with Java:
    • Application acts as an intermediary between the user and the database.
    • The application is built in Java, allowing users to interact with a console-based application.
  • JDBC (Java Database Connectivity):
    • JDBC is an API (Application Programming Interface) in the Java Development Kit (JDK).
    • Provides a standardized way for Java applications to connect with databases.
  • Challenges with Multiple DBMS:
    • Various database management systems (DBMS) exist, such as Oracle, Postgres, MySQL, H2, DB2.
    • Connecting Java applications to different DBMS requires specific implementation code.
  • Dynamic Implementation with JDBC:
    • JDBC API provides interfaces and classes for connectivity but requires actual implementation from the DBMS.
    • Each DBMS, like Postgres or MySQL, provides its implementation library for Java applications to connect.
  • Changing DBMS and Code Adaptation:
    • Changing DBMS, for example, from Postgres to MySQL, may require significant changes to the code.
    • JDBC simplifies this by providing a consistent API while leaving the implementation details to the specific DBMS library.
  • Series Focus on Postgres:
    • The series will use Postgres as the DBMS.
    • Installation of the chosen DBMS and acquiring the necessary library (JAR file) for connectivity will be covered in upcoming videos.
  • Next Steps:
    • Ensure the installation of the chosen DBMS.
    • Acquire the required JAR file/library for JDBC connectivity.
    • Explore the implementation of JDBC for connecting Java applications with the chosen database.

Postgres Setup

  • Setting Up Postgres:
    • Download Postgres from the official website: postgresql.org.
    • Install the appropriate version based on the operating system (Mac, Windows, Linux).
    • During installation, set a secure password for Postgres.
  • PgAdmin Interface:
    • PgAdmin is installed along with Postgres and provides a graphical interface for database management.
    • Access PgAdmin using the set password.
    • Familiarize with the Object Explorer, Servers, Database, and Dashboard sections.
  • Creating a Database:
    • In PgAdmin, right-click on Servers > Postgres version > Databases.
    • Create a new database, e.g., "Demo," with default settings and owner as "Postgres."
    • Explore the Database dashboard, schemas, and tables.
  • Creating a Table:
    • Right-click on Tables > Create Table.
    • Define a table name, e.g., "Student."
    • Specify columns like "Sid" (integer, primary key), "Sname" (text), "Marks" (integer).
    • Save to create the table.
  • Inserting Data:
    • Use the SQL query tool to insert data into the "Student" table.
    • Example query: INSERT INTO Student VALUES (1, 'Ahmed', 99);
    • Execute the query to insert data into the table.
    • View the inserted data in the table.
  • Troubleshooting Data Types:
    • Be mindful of data types during table creation (e.g., use "text" for string in Postgres).
    • In case of errors, alter the table structure or recreate columns with correct data types.
  • Viewing Data:
    • Use PgAdmin's graphical interface to view all rows in the table.
    • Explore the query tool to write SQL queries for data manipulation.
  • Next Steps:
    • The tutorial introduces manual database setup and data insertion.
    • Future lessons will focus on using JDBC to interact with the database from Java code.
    • JDBC will provide a programmatic way to connect, query, and manipulate the database using Java.

JDBC Steps

  • Steps for JDBC:
      1. Import Packages:
      • Import the java.sql package in Java, which contains classes and interfaces for JDBC operations.
      1. Load and Register Driver:
      • Load and register the JDBC driver specific to your database.
      • In JDBC versions prior to 4.0, this step was crucial, but newer versions (JDBC 4.0 onwards) often handle this automatically when adding the JDBC driver JAR to the project.
      1. Create a Connection:
      • Establish a connection to the database.
      • This is akin to having a working phone and network in a real-world analogy.
      1. Execute a Statement:
      • Prepare and execute SQL statements.
      • Analogous to thinking about what you want to say before making a call.
      1. Process the Result:
      • Handle the results obtained from the executed SQL statements.
      • Similar to processing the response received during a phone call.
      1. Close the Connection:
      • Properly close the connection to release resources and avoid memory leaks.
      • Similar to ending a phone call to prevent additional charges.
      1. Optional Steps (Depending on Version and Context):
      • Load and Register Driver (Optional):
        • Loading and registering the driver can be optional in certain JDBC versions and contexts, especially after JDBC 4.0.
      • Importing Packages (Optional):
        • Some tutorials or books might consider package importing as optional, focusing on essential steps.
    • Note:
      • The number of steps may vary in different resources, ranging from five to seven.
      • Steps 2 (Load and Register Driver) and 1 (Import Packages) can be optional depending on the JDBC version and project setup.
      • The key is to focus on the essential steps of creating a connection, executing statements, processing results, and closing the connection.

Postgres Library jar

    1. IDE Selection:
    • IntelliJ IDEA is chosen for coding in this section.
    • Both community (free) and ultimate (paid) versions are available, and the community version is used in this case.
    1. Project Setup:
    • A new project named "Jdbc course" is created in IntelliJ IDEA.
    • The language selected is Java, and the build system used is IntelliJ's default.
    1. JDK Version:
    • JDK 19 is used for the project, but any version above 8 is considered suitable.
    1. External Libraries (JDBC Driver):
    • The JDBC driver for PostgreSQL is required to establish a connection between Java and PostgreSQL.
    • The process involves downloading the JDBC driver JAR file from the official PostgreSQL website or Maven Repository.
    1. Library Integration:
    • In IntelliJ IDEA, the downloaded JAR file is added as an external library.
    • The steps include going to "File" > "Project Structure," selecting "Libraries," and adding the downloaded JAR.
    1. Code Development Steps (7 Steps in JDBC):
    • The speaker introduces the seven steps involved in JDBC, which include:
        1. Importing the necessary packages (e.g., java.sql).
        1. Loading and registering the JDBC driver (Note: JDBC 4.0 onwards may not require explicit loading and registration).
        1. Establishing a connection to the database.
        1. Executing a statement (equivalent to deciding what to say in a phone call analogy).
        1. Processing the results obtained from the database.
        1. Closing the connection to avoid memory leaks.
        1. Note: Some versions or sources may have different step counts, but the core steps remain the same.
    1. Coding Environment:
    • IntelliJ IDEA is suggested for coding in Java with JDBC.
    • The speaker indicates that the actual code implementation will follow in the next video.

Connecting Java and DB

    1. Coding Steps in JDBC:
    • The coding steps in JDBC are divided into seven key steps.
    • These steps are:
        1. Importing the necessary package (java.sql).
        1. Loading and registering the JDBC driver (optional in some cases).
        1. Creating a connection to the database.
        1. Creating a statement (equivalent to deciding what to say in a phone call analogy).
        1. Executing the statement.
        1. Processing the results obtained from the database.
        1. Closing the connection to avoid memory leaks.
    1. Importing Packages:
    • In the Java file, the first step involves importing the necessary package:
      • import java.sql.*;
    1. Loading and Registering Driver:
    • The second step, loading and registering the driver, is optional.
    • Example for PostgreSQL:
      • Class.forName("org.postgresql.Driver");
    1. Creating a Connection:
    • The third step involves creating a connection to the database using DriverManager.getConnection.
    • Example:
      • Connection con = DriverManager.getConnection(URL, username, password);
    1. Connection URL, Username, and Password:
    • The connection URL is specific to the type of database (e.g., PostgreSQL, MySQL, Oracle).
    • Example variables:
      • String URL = "jdbc:postgresql://localhost:5432/demo";
      • String username = "yourname";
      • String password = "pass";
    1. Testing Connection:
    • A test is performed to print "Connection established" on the console.
    • Initial mistakes are intentionally made to demonstrate error handling.
    • The test includes incorrect database type and incorrect password.
    1. Optional Driver Loading:
    • The driver loading step is optional, and in many cases, it's not explicitly required, especially with JDBC 4.0 and later versions.
    1. Error Handling:
    • The lecture emphasizes the use of try-catch for exception handling.
    1. Executing and Testing:
    • The code is tested with intentional errors for incorrect database type and password.
    • Corrections are made to ensure the successful establishment of a connection.
    1. Optional Steps:
    • Some steps are considered optional based on the specific JDBC version or use case.
    • The video demonstrates commenting out the driver loading step to show it's not compulsory in certain scenarios.

Execute and Process

    1. Connection Establishment:
    • Successful establishment of the database connection is confirmed.
    • Importing the package, loading the driver, and creating a connection are completed.
    1. Purpose of Database Connection:
    • The goal is to connect to a database using Java code for data retrieval.
    • The example uses a database named "demo" with a table named "Student" having three columns and one row.
    1. Objective: Fetching Data:
    • The primary purpose of connecting to the database is to fetch data, specifically the name of a student based on their ID.
    1. SQL Query for Data Retrieval:
    • The SQL query for fetching the name of a student with ID 1 is demonstrated.
    • Example: SELECT * FROM Student WHERE ID = 1
    1. Statement Creation:
    • To interact with the database, a Statement object is required.
    • A reference object for Statement is created using the createStatement method of the Connection object.
    1. Query Execution:
    • The executeQuery method of the Statement interface is used to execute the SQL query.
    • The result set is stored in a ResultSet object.
    1. Result Set Handling:
    • The ResultSet object is used to check if there is a next row using the next method.
    • The method returns true if there is a next row, false otherwise.
    1. Closing the Connection:
    • The importance of closing the connection is emphasized.
    • The close method is used to close the connection, ensuring proper resource management.
    1. Data Retrieval and Printing:
    • To retrieve and print data from the result set, methods like getString are used.
    • Data is fetched based on column names or column numbers.
    • Example: String name = rs.getString("sname");
    1. Error Handling:
    • The lecture mentions a crucial step that was initially overlooked: closing the connection.
    • No specific error-handling mechanisms are discussed in this segment.
    1. Pointer Positioning in Result Set:
    • Explanation of the default position of the result set pointer before the first row.
    • The importance of calling next to position the pointer correctly before fetching data.
    1. Successful Data Retrieval:
    • The successful execution of the program is demonstrated by fetching and printing the name of a student (Naveen) from the database.
    1. Teaser for Advanced Concepts:
    • The lecture ends with a teaser for upcoming topics, suggesting that more complex database interactions will be covered in the future.
  • Code 
    

    • 



import static java.lang.Class.*;
public class JDBCDemo {
public static void main(String[] args) throws ClassNotFoundException, SQLException {


  String URL = "jdbc:postgresql://localhost:5432/Demo";
  String username = "postgres";
  String password = "root";

  Class.forName("org.postgresql.Driver");
  Connection con = DriverManager.getConnection(URL, username, password);

  System.out.println("Connection Established");

  // Your SQL query
  String sql = "SELECT sname FROM student WHERE sid = 1";

  // Create a statement
  Statement st = con.createStatement();

  // Execute the query
  ResultSet rs = st.executeQuery(sql);

  // Move to the first row in the result set
  if (rs.next()) {
      // Retrieve the value of the "sname" column
      String name = rs.getString("sname");

      // Print the result
      System.out.println("Name of a student is " + name);
  } else {
      System.out.println("No records found.");
  }

  // Close the resources
  rs.close();
  st.close();
  con.close();
  System.out.println("Connection Closed");



}
} ```


Fetching all Records


    

  • 

      

    1. Objective: Inserting Data into Database
      2. 

    

      

    • Goal: Insert data into the database for fetching with different IDs.
      • 

    • Utilize SQL queries for inserting records into the "Student" table.
      • 

    

    • 

  • 

      

    1. SQL Insert Queries:
      2. 

    

      

    • Example SQL queries:

        

      • Inserting data for ID 2: INSERT INTO student VALUES (2, 'Kiran', 50);
        • 

      • Inserting data for ID 3: INSERT INTO student VALUES (3, 'Hirsch', 55);
        • 

      • Inserting data for ID 4: INSERT INTO student VALUES (4, 'Social', 45);
        • 

      

      • 

    

    • 

  • 

      

    1. Verifying Inserted Data:
      2. 

    

      

    • Execute a SELECT query to verify that the data has been successfully inserted.
      • 

    • Example: SELECT * FROM student;
      • 

    

    • 

  • 

      

    1. Updating Java Code for Data Retrieval:
      2. 

    

      

    • Modify the Java code to fetch and print all rows and columns from the "Student" table.
      • 

    

    • 

  • 

      

    1. Using ResultSet for Data Retrieval:
      2. 

    

      

    • Utilize the ResultSet object to iterate over rows and retrieve data for each column.
      • 

    

    • 

  • 

      

    1. Automating Data Retrieval with a Loop:
      2. 

    

      

    • Use a while loop to iterate over rows until there is no next row.
      • 

    • The next method checks for the next row and moves the pointer.
      • 

    

    • 

  • 

      

    1. Fetching Data Using Column Numbers:
      2. 

    

      

    • Fetch data from the result set using both column numbers and column names.
      • 

    • Example: int id = rs.getInt(1); or String name = rs.getString("sname");
      • 

    

    • 

  • 

      

    1. Printing Data in a Readable Format:
      2. 

    

      

    • Print data with appropriate formatting to distinguish between rows and columns.
      • 

    

    • 

  • Now, here is the complete code snippet used in this tutorial:

    import java.sql.*;
public class JDBCDemo {
  public static void main(String[] args) {
      try {
          String URL = "jdbc:postgresql://localhost:5432/Demo";
          String username = "postgres";
          String password = "root";

          // Load the PostgreSQL JDBC driver
          Class.forName("org.postgresql.Driver");

          // Establish a connection
          Connection con = DriverManager.getConnection(URL, username, password);

          System.out.println("Connection Established");

          // Create a statement
          Statement st = con.createStatement();

          // Fetching all rows and columns
          String query = "SELECT * FROM student";
          ResultSet rs = st.executeQuery(query);

          // Iterating over rows and printing all columns
          while (rs.next()) {
              int id = rs.getInt("sid");
              String name = rs.getString("sname");
              int marks = rs.getInt("smarks");

              // Printing data with proper formatting
              System.out.println("ID: " + id + " - Name: " + name + " - Marks: " + marks);
          }

          // Closing the resources
          rs.close();
          st.close();
          con.close();
          System.out.println("Connection closed");
      } catch (ClassNotFoundException | SQLException e) {
          e.printStackTrace();
      }
  }
}```

      
    

    • 



Crud operations


    

  • Fetching Data

      

    • Fetching a single data item and printing the entire table.
      • 

    • Use of a while loop to count the number of rows.
      • 

    • Possibility of automating column retrieval with an additional loop.
      • 

    • Use of a for loop for columns to execute queries.
      • 

    

    • 

  • Inserting Data

      

    • Explanation of CRUD operations (Create, Read, Update, Delete).
      • 

    • Changing SQL query to an insert query for adding a new record.
      • 

    • Executing the insert query using execute method.
      • 

    • Handling the Boolean status returned by execute.
      • 

    

    • 

  • Updating Data

      

    • Changing SQL query to an update query.
      • 

    • Updating a specific record (e.g., changing a name from John to Max).
      • 

    • Executing the update query using execute.
      • 

    

    • 

  • Deleting Data

      

    • Changing SQL query to a delete query.
      • 

    • Deleting a specific record (e.g., deleting the record with ID 5).
      • 

    • Executing the delete query using execute.
      • 

    

    • 

  • Code Snippet:
    • 

  • 

      - // Establishing the connection (common for all operations)
Connection con = DriverManager.getConnection(URL, username, password);
Statement stmt = con.createStatement();

// Inserting Data
String insertQuery = "INSERT INTO student VALUES (5, 'John', 48)";
boolean insertStatus = stmt.execute(insertQuery);
System.out.println("Insert Status: " + insertStatus);

// Updating Data
String updateQuery = "UPDATE student SET name = 'Max' WHERE ID = 5";
boolean updateStatus = stmt.execute(updateQuery);
System.out.println("Update Status: " + updateStatus);

// Deleting Data
String deleteQuery = "DELETE FROM student WHERE ID = 5";
boolean deleteStatus = stmt.execute(deleteQuery);
System.out.println("Delete Status: " + deleteStatus);

// Closing the connection
stmt.close();
con.close();```
    

    • 



Problems with Statement


    

  • 

      

    1. Introduction to Prepared Statements:
      2. 

    

      

    • Prepared statements are used in SQL to improve performance, avoid SQL injection, and simplify the process of inserting data into a database.
      • 

    • They are particularly useful when dealing with user input, as they help prevent SQL injection vulnerabilities.
      • 

    

    • 

  • 

      

    1. Need for Prepared Statements:
      2. 

    

      

    • Directly inserting data using concatenation and double quotes can lead to issues.
      • 

    • Problems include treating values as strings, complex concatenation, and the risk of SQL injection attacks.
      • 

    • Performance improvement is achieved by caching queries in the database.
      • 

    

    • 

  • 

      

    1. Issues with Direct Insertion:
      2. 

    

      

    • Direct insertion involves concatenating values within double quotes, making it error-prone and confusing.
      • 

    • SQL injection vulnerabilities arise when user input is directly incorporated into queries.
      • 

    

    • 

  • 

      

    1. Benefits of Prepared Statements:
      2. 

    

      

    • Improved performance by caching queries.
      • 

    • Prevention of SQL injection attacks.
      • 

    • Simplification of the process of inserting data into a database.
      • 

    

    • 

  • 

      

    1. Preventing SQL Injection:
      2. 

    

      

    • SQL injection occurs when user input contains malicious SQL code.
      • 

    • Prepared statements help prevent SQL injection by separating SQL code from user input.
      • 

    

    • 

  • 

      

    1. Improving Performance with Prepared Statements:
      2. 

    

      

    • Caching queries in the database is a key feature of prepared statements.
      • 

    • Reusing the same query multiple times without resending it from Java to the database.
      • 

    

    • 

  • Code Snippet:

    - // Direct insertion with concatenation (not recommended)
String query = "INSERT INTO student VALUES (" + CID + ", '" + name + "', " + marks + ")";
Statement statement = connection.createStatement();
statement.executeUpdate(query);

// Issues with direct insertion and potential SQL injection vulnerabilities

// Prepared statement example (to be covered in the next video)
String preparedQuery = "INSERT INTO student VALUES (?, ?, ?)";
PreparedStatement preparedStatement = connection.prepareStatement(preparedQuery);
preparedStatement.setInt(1, CID);
preparedStatement.setString(2, name);
preparedStatement.setInt(3, marks);
preparedStatement.executeUpdate(); ```
    

    • 



PreparedStatement


    

  • 

      

    1. Introduction to Prepared Statements:
      2. 

    

      

    • Prepared statements are used to improve code readability, prevent SQL injection, and enhance performance.
      • 

    • They are particularly useful when dealing with dynamic data coming from variables.
      • 

    

    • 

  • 

      

    1. Building a Prepared Statement:
      2. 

    

      

    • Instead of directly inserting values into the SQL query, use placeholders (question marks) for dynamic data.
      • 

    • Example: INSERT INTO student VALUES (?, ?, ?)
      • 

    

    • 

  • 

      

    1. Using Prepared Statement in Java:
      2. 

    

      

    • Replace Statement with PreparedStatement when working with dynamic data.
      • 

    • PreparedStatement pstmt = con.prepareStatement(sql);
      • 

    

    • 

  • 

      

    1. Precompilation of Query:
      2. 

    

      

    • Prepared statements are precompiled, allowing for better performance and caching of queries.
      • 

    • The SQL query is set during the creation of the prepared statement.
      • 

    

    • 

  • 

      

    1. Setting Parameters in Prepared Statement:
      2. 

    

      

    • Use set methods to set parameters for the prepared statement.
      • 

    • setInt(int parameterIndex, int x), setString(int parameterIndex, String x), etc.
      • 

    • Parameters are replaced with actual data during execution.
      • 

    

    • 

  • 

      

    1. Column Index in Prepared Statement:
      2. 

    

      

    • Columns are indexed starting from 1 in prepared statements.
      • 

    • Example: setInt(1, CID) sets the value of the first parameter to the value of CID.
      • 

    

    • 

  • 

      

    1. Data Types in Prepared Statement:
      2. 

    

      

    • Specify the data type using appropriate set methods (e.g., setInt, setString) based on the column type.
      • 

    

    • 

  • 

      

    1. Benefits of Prepared Statements:
      2. 

    

      

    • Cleaner and clearer code compared to concatenation.
      • 

    • Prevention of SQL injection vulnerabilities.
      • 

    • Improved performance through precompilation and caching.
      • 

    

    • 

  • 

      

    1. Example Code:
      2. 

    

    - // Creating a prepared statement
String sql = "INSERT INTO student VALUES (?, ?, ?)";
PreparedStatement pstmt = con.prepareStatement(sql);

// Setting parameters for the prepared statement
pstmt.setInt(1, CID);
pstmt.setString(2, name);
pstmt.setInt(3, marks);
// Executing the prepared statement
pstmt.executeUpdate();``` 
    

    • 

  • 

      

    1. Versatility of Prepared Statements:
      2. 

    

      

    • Prepared statements can be used not only for insertion but also for deletion, update, and select operations.
      • 

    • Dynamic data is handled using placeholders that are replaced at runtime.
      • 

    

    • 

  • 

      

    1. Verification and Testing:
      2. 

    

      

    • Execute the prepared statement to ensure it works as expected.

        

      • Verify the results in the database to confirm the insertion.
        • 

      

      • 

    

    • 



Section 4: Getting Started


Introduction to Spring


    

  • 

      

    1. Introduction to Spring Framework:
      2. 

    

      

    • Spring Framework is a comprehensive framework for Java development.
      • 

    • Considered one of the best frameworks for Java, offering a wide range of features and functionalities.
      • 

    

    • 

  • 

      

    1. Evolution of Java Frameworks:
      2. 

    

      

    • Mention of previous frameworks like Struts and EJB for enterprise development.
      • 

    • Spring has become a popular choice due to its versatility and features.
      • 

    

    • 

  • 

      

    1. Focus on POJO (Plain Old Java Objects):
      2. 

    

      

    • Spring emphasizes the use of POJOs for development.
      • 

    • Contrasts with EJB, where the focus was on Entities.
      • 

    • Enables developers to achieve various tasks without the need for heavyweight components.
      • 

    

    • 

  • 

      

    1. Spring as a Collection of Modules:
      2. 

    

      

    • Spring is not a monolithic framework; it comprises multiple projects/modules.
      • 

    • Each module addresses specific concerns or features.
      • 

    • Examples include modules for dependency injection, web development, REST, security, and database connectivity.
      • 

    

    • 

  • 

      

    1. Dependency Injection in Spring:
      2. 

    

      

    • Introduction to Dependency Injection (DI) as a common feature of Spring.
      • 

    • Dependency Injection is achieved using the Spring Core module.
      • 

    

    • 

  • 

      

    1. Web Development with Spring MVC:
      2. 

    

      

    • Spring MVC is a module within the Spring Framework focused on web development.
      • 

    • Provides features and components for building web applications.
      • 

    

    • 

  • 

      

    1. Building RESTful Applications with Spring:
      2. 

    

      

    • Spring offers a dedicated module for building RESTful applications.
      • 

    • Enables the creation of APIs following REST principles.
      • 

    

    • 

  • 

      

    1. Security in Spring:
      2. 

    

      

    • Spring provides modules for handling security aspects in applications.
      • 

    • Developers can leverage Spring for implementing secure authentication and authorization.
      • 

    

    • 

  • 

      

    1. Database Connectivity with JPA in Spring:
      2. 

    

      

    • Spring includes modules for integrating with Java Persistence API (JPA) for database connectivity.
      • 

    • Offers convenient features for database interaction.
      • 

    

    • 

  • 

      

    1. Modularity and Extensibility:
      2. 

    

      

    • Spring's modular architecture allows developers to use only the modules relevant to their application.
      • 

    • Extensibility enables integration with other frameworks and technologies.
      • 

    

    • 

  • 

      

    1. Overview of Spring Modules:
      2. 

    

      

    • Discussion about various modules, including Spring Core, Spring MVC, Spring REST, and more.
      • 

    • Each module serves a specific purpose, providing a tailored approach to application development.
      • 

    

    • 

  • 

      

    1. Developer's Focus on Application Development:
      2. 

    

      

    • Spring Framework allows developers to focus more on application development.
      • 

    • Handles many underlying concerns such as security, database connectivity, and dependency injection.
      • 

    

    • 



Spring Documentation


    

  • The official website of Spring is spring.io, developed by Pivotal.
    • 

  • Spring has various projects, including Spring Boot, Spring Framework, Spring Cloud, Spring Data, and Spring Security.
    • 

  • The documentation for Spring is extensive and can be accessed in various formats, including EPUB and online.
    • 

  • The documentation provides detailed information and guides for using different components of Spring.
    • 



Prerequisites


    

  • Prerequisites for working with Spring framework include knowledge of Java, database connectivity, Servlet and JSP, and ORM frameworks like Hibernate. Optional concepts include understanding of internet protocols, Spring Security, LDAP, and OAuth.
    • 

  • Highlights

      

    • 💡 Prerequisites for Spring include Java, database connectivity, Servlet and JSP, and ORM frameworks.
      • 

    • 💡 Optional concepts include internet protocols, Spring Security, LDAP, and OAuth.
      • 

    

    • 

  • Bullet Points

      

    • 💻 Knowledge of Java, including OOPs, exception handling, threads, and loops, is essential for working with Spring.
      • 

    • 🗄️ Understanding database connectivity, such as MySQL or Postgres with Java, is important.
      • 

    • 🌐 Familiarity with Servlet and JSP is necessary as all Spring applications run on a servlet container like Tomcat.
      • 

    • 📚 Knowledge of ORM frameworks like Hibernate or iBATIS is recommended.
      • 

    • 🌍 Optional concepts to learn include internet protocols, Spring Security, LDAP, and OAuth.
      • 

    

    • 



Software Requirement


    

  • It is recommended to use an Integrated Development Environment (IDE) for writing and running the code.
    • 

  • Some popular IDEs for Java development are NetBeans, Eclipse, and IntelliJ.
    • 

  • Spring Tool Suite (STS) is a separate IDE provided by Spring for writing Spring code. It is based on Eclipse and can be downloaded for free.
    • 

  • STS is not mandatory to use, and you can still use NetBeans or Eclipse if you prefer.
    • 

  • STS can be downloaded from the official Spring website.
    • 

  • STS is essentially Eclipse with a Spring layer on top, so if you are familiar with Eclipse, you will have no trouble using STS.
    • 

  • It is recommended to have JDK (Java Development Kit) installed before installing STS.
    • 

  • The suggested JDK version for working with Spring 5 is JDK 8, as it supports the required features like reactive programming and lambda expressions.
    • 

  • However, Spring 5 also supports Java 9, so if you have Java 9 installed, you can use its features as well.
    • 

  • Once the STS download is complete, it needs to be installed
    • 



Spring Tool Suite (STS)


    

  • Spring Tool Suite (STS) is a development environment based on Eclipse that is specifically designed for developing Spring applications.
    • 

  • To install STS, you need to unzip the downloaded zip file and ensure that you give the unzipped folder a small name to avoid issues.
    • 

  • STS includes a pre-configured version of Tomcat called Pivotal tc-server, which eliminates the need to download Tomcat separately.
    • 

  • STS looks and functions similar to Eclipse, as it is built on the Eclipse platform.
    • 

  • The main sections of STS are the Project section (where all the projects are located), the code editor area, and the console section (where logs are printed).
    • 

  • STS supports the creation of various types of projects, including Spring setup projects, Spring legacy projects, and Java projects.
    • 

  • When working with the Spring framework, it is necessary to add Spring dependencies to the project.
    • 

  • Maven, a build tool, can be used to manage dependencies and automatically download them for the project.
    • 

  • To create a Maven project in STS, you need to select the "Maven Project" option and provide a name and group ID for the project.
    • 

  • Maven uses a pom.xml file to specify dependencies. You can add additional dependencies by editing the pom.xml file.
    • 

  • Gradle is an alternative build tool to Maven that can also be used in STS.
    • 

  • To find and download dependencies, you can search for them on the Maven Repository website and copy the dependency information into the pom.xml file.
    • 

  • STS automatically downloads the specified dependencies when the project is built.
    • 

  • After adding the necessary dependencies, you can start writing your Spring application
    • 



Dependency Injection


    

  • 

      

    1. Introduction to Spring Core:
      2. 

    

      

    • Spring Core is a fundamental module in the Spring Framework.
      • 

    • Addresses the issue of dependencies in software development.
      • 

    

    • 

  • 

      

    1. Understanding Object-Oriented Programming (OOP):
      2. 

    

      

    • In Java, everything is treated as an object in object-oriented programming.
      • 

    • Objects have properties and behaviors.
      • 

    

    • 

  • 

      

    1. Challenge with Object Creation:
      2. 

    

      

    • Creating multiple objects can be cumbersome and error-prone.
      • 

    • Issues arise when managing the lifecycle of objects and their dependencies.
      • 

    

    • 

  • 

      

    1. Dependency Injection (DI):
      2. 

    

      

    • Dependency Injection is a key concept in Spring Core.
      • 

    • It addresses the challenges of managing object dependencies by injecting them from outside the class.
      • 

    

    • 

  • 

      

    1. Example of Building a Laptop:
      2. 

    

      

    • Illustration of the need for dependencies in building a laptop.
      • 

    • A laptop requires components like a hard drive, RAM, CPU, etc.
      • 

    

    • 

  • 

      

    1. Issues with Manual Object Creation:
      2. 

    

      

    • Manual creation of objects leads to responsibility for managing their lifecycle and destruction.
      • 

    • Lack of flexibility when dealing with changing requirements.
      • 

    

    • 

  • 

      

    1. Dependency Injection and Inversion of Control (IoC):
      2. 

    

      

    • Dependency Injection is often synonymous with Inversion of Control (IoC).
      • 

    • IoC means that the control over object creation and management is inverted or delegated to a container (Spring, in this case).
      • 

    

    • 

  • 

      

    1. Role of a Dependency Injection Container:
      2. 

    

      

    • Spring acts as a Dependency Injection Container.
      • 

    • The container is responsible for managing the creation, configuration, and lifecycle of objects.
      • 

    

    • 

  • 

      

    1. Advantages of Dependency Injection in Spring:
      2. 

    

      

    • Decouples the class from its dependencies, promoting modularity.
      • 

    • Easier to test as dependencies can be mocked or replaced.
      • 

    • Promotes a cleaner and more maintainable codebase.
      • 

    

    • 

  • 

      

    1. Configuration in Spring Core:
      2. 

    

      

    • Configuration is required to enable dependency injection in Spring.
      • 

    • The configuration specifies how dependencies are injected into the application.
      • 

    

    • 

  • 

      

    1. Inversion of Control (IoC) in Spring:
      2. 

    

      

    • IoC in Spring means that the framework takes control of managing the objects and their dependencies.
      • 

    • Developers don't need to create and manage objects manually.
      • 

    

    • 

  • 

      

    1. Configuration in Spring Core:
      2. 

    

      

    • Configuration involves specifying the dependencies in a configuration file or using annotations.
      • 

    • Spring will then inject the dependencies at runtime.
      • 

    

    • 

  • 

      

    1. Introduction to "Magic" and Configuration:
      2. 

    

      

    • Acknowledgment that configuration is required, but Spring simplifies the process.
      • 

    • It might seem like magic, but it's achievable through proper configuration.
      • 

    

    • 



Section 5: Spring Boot


Section 6: Spring Core - loC


Section 7: Spring MVC


Section 8: Spring ORM


Section 9: Spring Data JPA


Section 10: Spring REST


Section 11: Spring AOP


Section 12: Spring Security


Section 13: Docker


Section 14: Microservices


Section 15: DSA (Optional)