Gain insights into Java 17, cloud and microservices, reactive programming, and top JVM languages. Explore hands-on projects using Scala, Groovy, and Gradle to boost your software development career.

Modern Java Second Edition by Adam L. Davis.png

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Groovy

Scala

Java 12

Java 14

Java 16

Java 17

Java 16-copy

Play

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SPA-play

Gradle-uppercase

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Gradle-properties

Java 14-copy

Java 16-fruits

Java 16-strings

Gradle-java

This course is meant for Java programmers or aspiring programmers who want to know about the latest Java and JVM technology. Throughout this course, you will get several opportunities to get hands-on experience with various Java concepts. 

This course will help you understand the latest in Java up to version 17; cloud and microservices; build, testing, and web frameworks; reactive programming in Java; and the best JVM languages so you can advance your career in software development. 

Moreover, you will also get to work with Scala, Groovy, and Gradle. The course explains Java concepts in detail and also draws comparisons with its older versions, as well as JVM languages.

The All-in-One Guide to Java Programming

## SpringBootApplication
The main class is specified by annotating it with `@SpringBootApplication`. Create a file named "DemoApplication.groovy" in the `com.example.demo` package, and put the following:

```
package com.example.demo

import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication


@SpringBootApplication
class DemoApplication {
      static void main(String[] args) {
         SpringApplication.run DemoApplication, args //1
      }
      @Bean
      Service sampleServier() { new SampleService() } //2
}
```
1. The main method calls `SpringApplication.run` to start the application.
2. Beans can be created directly using the `@Bean` annotation on methods

The `@SpringBootApplication` annotation tells Spring a number of things:
1. To use auto-configuration.
2. To use component scanning. Scanning all packages for classes annotated with Spring annotations.
3. This class is a Java-based configuration class, so you can define beans here using the @Bean
annotation on a method that returns a bean.

Alternatively, if you want to specify web-service mappings more directly, you can use the `@Controller` and `@RequestMapping` annotations like the following, `hello/SampleController.java`:

```
package hello;

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;

@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
     return "Hello World!";
    }

    public static void main(String[] args) throws Exception {
      SpringApplication.run(SampleController.class, args);
    }
}
```
Of course, this would be a much smaller application. For larger projects, you should use the
`@SpringBootApplication` approach.


# SpringBootApplication
The main class is specified by annotating it with `@SpringBootApplication`. Create a file named "DemoApplication.groovy" in the `com.example.demo` package, and put the following:

```
package com.example.demo

import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication


@SpringBootApplication
class DemoApplication {
      static void main(String[] args) {
         SpringApplication.run DemoApplication, args //1
      }
      @Bean
      Service sampleServier() { new SampleService() } //2
}
```
1. The main method calls `SpringApplication.run` to start the application.
2. Beans can be created directly using the `@Bean` annotation on methods

The `@SpringBootApplication` annotation tells Spring a number of things:
1. To use auto-configuration.
2. To use component scanning. Scanning all packages for classes annotated with Spring annotations.
3. This class is a Java-based configuration class, so you can define beans here using the @Bean
annotation on a method that returns a bean.

Alternatively, if you want to specify web-service mappings more directly, you can use the `@Controller` and `@RequestMapping` annotations like the following, `hello/SampleController.java`:

```
package hello;

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;

@Controller
@EnableAutoConfiguration
public class SampleController {

    @RequestMapping("/")
    @ResponseBody
    String home() {
     return "Hello World!";
    }

    public static void main(String[] args) throws Exception {
      SpringApplication.run(SampleController.class, args);
    }
}
```
Of course, this would be a much smaller application. For larger projects, you should use the
`@SpringBootApplication` approach.


Demo Application

Introduction

Java Syntax and Conventions

Java 7

Idiomatic Java 8: Lambdas, Streams, and Dates

New Date and Time API

Java 8 Miscellaneous

Advantages of Java 9

Java 10 - 17

Java Ecosystem

Maven and JUnit

Utilizing Essential Libraries

Modern Java Concurrency

RxJava

Other JVM Languages

Groovy

Gradle

Spock

Scala

RESTful

Microservices and Clouds

Grails

Spark

Spring Boot

Play Framework

Ratpack

Final Thoughts

Appendix

Demo Application

SpringBootApplication