initializr | HTML5 Boilerplate Custom Builder running on Google App

I'm in a Spring course, and I have a maven application (downloaded from the course resources) built from spring initializr. I can build a local Docker image with mvn spring-boot:build-image (no Dockerfile in the project). By default a Docker image is built as linux/amd64, but I am working with a M1 Apple Silicon chip (arm64). I've been looking many workarounds but with no success. Lastly, I found that maybe adding a Dockerfile and specifying the platform it would build the image accordingly.

My goal is to build a docker image for arm64 architecture.

So, I created a Dockerfile:

I am new to Gradle and I followed the instructions of a tutorial, just that instead of maven I chose Gradle in Spring.Initializr.

It produced following code for the build.gradle

I downloaded Intellij to follow a Springboot tutorial. It begins by going to Spring Initializr to get all relevant dependencies in a folder and open it up on Intellij. As I open up Intellij, the run button is not visible. Instead it says "Add Configuration".

If I open up Intellij for a normal java program, I was easily able to click run and choose "Main.java"

This is a freshly installed Intellj and settings were set up as default. Is there a trick to find the run button when dealing with Springboot? I tried doing as if it was a normal program but as you can see, I can't find it. I tried looking up similar questions but there doesn't seem any that matches mine. I would appreciate any help. Thank you!

EDIT 1: I tried right clicking on src directory and select option Mark Directory As > Sources Root. But breaks program instead.

EDIT 2: I tried adding a new configuration --> Add new --> Application --> then look for Main class entitled 'DemoApplication' but its not found. (I thought that this would be my main class)

For years, I've used Spring Initializr (at https://start.spring.io/) to create the initial SpringBoot application and then modify it to create the app. This works fine.

Is there a maven archetype I can use to create a SpringBoot app? Or is the Spring Initializr the only way to do this.

Searching I found this:

• What archetype to choose for a simple java project

Which shows the command:

I've written some tests in which I use org.springframework.core.io.ClassPathResource to get file that will be sent to API. One to the requirements were to support unicode characters in the filename so I've loaded file containing random mix of unicode characters and it failed to decode URI. After some diagnostics it seems like this cute boy of character "🐱" (cat emoji, U+1F431) is breaking it. I've encoded it using unicode escape ("\u") for Java literals in case something is wrong with IDE encoding/view. But nothing changed. So I've created the demo using Spring Boot initializr in case some packages had any effect and began debugging. From testing it seems that characters that can be encoded using single "\u" escape sequence work just fine (GAMMA did work) but those that need to use surrogate pairs don't eg. 🐱 being "\uD83D\uDC31".

URL encoded emoji/filename in question looks like this %ed%a0%bd%ed%b0%b1 comes from sun.net.www.ParseUtil.encodePath(String path, boolean flag), while error is thrown in the same class but decode(String path) method. I couldn't use ParseUtil myself directly because it wasn't accessible even though it's public. Can anyone explain what is going on here? Is it just a bug in ParseUtils/Java or I'm missing something?

I'm using Java 11 zulu on Windows 10.

Demo that I used:

I created a Spring Boot demo app with Maven using Spring Initializr (that's my almost the very first usage of Spring). It works, but for some reason doesn't show any pages besides index.html. If I'm right, that's because of configuration in application.properties, but I just don't know, what have I add there.

My project's sources structure:

I have a Spring Boot stub project just generated on Spring Initializr, with pnpm preinstalled, but currenty no npm is installed, runned on Windows 10 with mvn spring-boot:run

The pom.xml is:

I created a project with spring initializr with kotlin and gradle to study hexagonal architecture in microservices. I'm using IntelliJ with modules to dividing the code but the spring-jpa dependency doesn't work in module (or subproject).

The start build.gradle.kts is:

i create an empty new spring boot project with Spring initializr with the dependency