https://github.com/blaze-b/mc-java-demo-trainer

A complete java e2e features testing and running it make it workable solutions to be taken later
https://github.com/blaze-b/mc-java-demo-trainer

java servelet spring spring-boot spring-mvc

Last synced: about 2 months ago
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A complete java e2e features testing and running it make it workable solutions to be taken later

• Host: GitHub
• URL: https://github.com/blaze-b/mc-java-demo-trainer
• Owner: blaze-b
• Created: 2020-11-07T09:27:47.000Z (about 4 years ago)
• Default Branch: master
• Last Pushed: 2024-11-02T22:24:45.000Z (3 months ago)
• Last Synced: 2024-11-02T23:19:55.404Z (3 months ago)
• Topics: java, servelet, spring, spring-boot, spring-mvc
• Language: Java
• Homepage:
• Size: 618 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Java Essential Training

## History

- A new portable language

- Original Name: Oak

- Tag line: Write once, Run Everywhere

![Alt text](images/History.PNG "History of Java")

![Alt text](images/History2.PNG "History of Java")

## Principles

- Simple, Object-oriented, and familiar

- Robust and secure(Methods, properties and Debugging)

- Architecture-neutral and portable

- High-performance

- Interpreted, threaded(more than one processes) and dynamic

## Runtime Architecture

- It is an interpreted language.

- It compiles the bytecode instead of machine language

- The compiled application is portable between platforms without recompiling(JVM)

![Alt text](images/Runtime_Arch.PNG "Runtime Architecture")

## Java v/s JavaScript

![Alt text](images/JavaVsJavaScript.PNG "History of Java")

## Features

- Java Platform, Micro Edition(ME) (Micro-Controller, sensors and mobile devices)

- Java Runtime Environment (Java SE Runtime Environment (JRE) includes JVM),

Supported on Windows, Linux, OS X and Solaris, Runs all java applications: desktop, browser and server,

Must be updated to keep up with the security issues, Mobile operating systems have their own runtimes.

- Java development kit(JDK): It is a no cost from ORACLE, Include tools for the compilation and packaging


  - java: runtime

  - javac: compile

  - javadoc: docs builder

  - jar: archive builder

## Creating classes

- All codes are defined in classes

- Classes are defined in the src code files with .java extensions

- javac command compiles Java code into byte code

## Identifier Conventions

- Classes start with the uppercase character, class MyClass{}

- Methods and variables start with the lowercase character.


```java

    void doSomething() {

    }

```

- Constants are always UpperCase

```java

    public static final String FIRST_NAME = "david";

```

## Memory management and Garbage collection

- Automatic Memory Management (Memory for objects is allocated automatically)

- Objects are created in the heap memory

- As long as any variable references an object, its's retained

- When all the references expire, then it is available for the garbage collection

## Reference Expire?

- Variables local to methods or code blocks expire with scope,


```java

    void checkString() {

        String localVar = "Test String";

        System.out.println("Tes" + localVar);

    }

    

```

- We can defer variable with the null keyword,

```java

String tempVar = "Test string";

tempVar = null;

```

## Servlets

- Install the tomcat version: https://tomcat.apache.org/download-90.cgi

- After installing the server import it in the intelliJ smart tomcat runner plugin: `D:\dev\software\apache-tomcat-9.0.91`,

  - Setting up the tomcat path

      ![Alt text](images/tomcat-setting.jpg "Setting up the tomcat path")

  

  - Setting up the tomcat runner details

      ![Alt text](images/tomcat-runner-setting.jpg "Setting up the tomcat runner details") 

## Design Patterns

For every software architectural processes the design principles plays crucial role in development, [Design patterns](/docs/java-design-pattern.md)