Introduction

A Bank of America recruiter reach out to me today asking if I'd be interested in an opportunity there.

He mentioned Java & Spring Boot were requirements for the role.

I've used Java to implement a few native modules in React Native in the past.

I've also used it on Leetcode because it's a popular language in enterprise applications and I want to one day be able to work on that level.

Lastly I've built a few simple Android applications(Udemy tutorials).

So I decided to setup a new Spring Boot project on my local in order to familiarize myself with it.

There are many recommended IDEs for Java but I went with VSCode because it's what I'm familiar with and I wanted to move quickly.

I ended up having to install the following to be able to run it using VSCode and find a running web server at http://localhost:8080.

Here are the steps I took to Hello World Spring Boot

Download and install Java SDK on my local

https://www.oracle.com/java/technologies/downloads/

Define path to the Java executable inside bash profile

JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-19.jdk/Contents/Home" PATH="${JAVA_HOME}/bin:${PATH}" export PATH

Install Java extension pack for VSCode

https://marketplace.visualstudio.com/items?itemName=vscjava.vscode-java-pack

Install Spring Initializr for VSCode

This extension allows you to generate new Spring projects sorta like npx create-react-app allows you to generate new React projects.

https://code.visualstudio.com/docs/java/java-spring-boot

Use Spring Initializr to generate a new Spring application

This tool creates a directory with a bunch of config files. In this way it's similar to Ruby on Rails/Django/.Net

.
├── HELP.md
├── mvnw
├── mvnw.cmd
├── pom.xml
├── src
│   ├── main
│   │   ├── java
│   │   │   └── com
│   │   │       └── example
│   │   │           └── restapi
│   │   │               └── demo
│   │   │                   ├── DemoApplication.java
│   │   └── resources
│   │       ├── application.properties
│   │       ├── static
│   │       └── templates
│   └── test
│       └── java
│           └── com
│               └── example
│                   └── restapi
│                       └── demo
│                           └── DemoApplicationTests.java

The directory is familiar to Android developers as both Android and Spring use Gradle

The most important file is DemoApplication.java which is the entrypoint to our application.

Define new route/api/endpoint

In order to create additional endpoints we just have to define a controller at the same path as this file. In my case I created GreetingController.java.

Additional I defined Greeting.java

.
├── HELP.md
├── src
│   ├── main
│   │   ├── java
│   │   │   └── com
│   │   │       └── example
│   │   │           └── restapi
│   │   │               └── demo
│   │   │                   ├── DemoApplication.java
│   │   │                   ├── Greeting.java
│   │   │                   └── GreetingController.java

Implement `Greeting.java` class

Java is a lot more verbose than languages such as Python, Ruby, JS. I guess this is why boot camps prefer those languages for beginners.

package com.example.restapi.demo;
 
public class Greeting {
 
	private final long id;
	private final String content;
 
	public Greeting(long id, String content) {
		this.id = id;
		this.content = content;
	}
 
	public long getId() {
		return id;
	}
 
	public String getContent() {
		return content;
	}
}

Implement `GreetingController.java` class

Here's the controller which defines the endpoint we use to test the application, http://localhost:8080/greeting.

package com.example.restapi.demo;
 
import java.util.concurrent.atomic.AtomicLong;
 
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
 
@RestController
public class GreetingController {
 
	private static final String template = "Hello, %s!";
	private final AtomicLong counter = new AtomicLong();
 
	@GetMapping("/greeting")
	public Greeting greeting(@RequestParam(value = "name", defaultValue = "World") String name) {
		return new Greeting(counter.incrementAndGet(), String.format(template, name));
	}
}

Should now see logs in the console

Spring

WORKSPACE