spring boot hotswap with Intellij IDE

Question

I have a spring boot application running fine with Intellij IDE. i.e i started the Application class that has the main method which delegates to SpringApplication.run. Everything works great except hotswap. When I change the source, I am forced to re-start the application. Even If I start the application in debug mode, I dont see hotswap working. I could see that Intellij's Debug settings have hotswap enabled.

My observation shows that when I run the springboot application, classpath used is my

/projects/MyProject/classes/production/....

Files under classes/production are not getting updated when I change the code. Intellij IDE compiles the files but does not update classes/production directory. How do I get hotswap working with IntelliJ IDE for spring-boot?

Druse

check this out #21400086 – Glengarry

Answer 1

Found out the root cause. This has nothing to do with Spring-boot. On changing my groovy source files, files were not auto-compiled.

To recompile changed files and swap them:

• Ctrl+Shift+F9 on Windows
• Cmd+Shift+F9 on Mac

Druse

How to diable restart project every time when one file is changed – Deane

You can use a trigger file. See: docs.spring.io/spring-boot/docs/current/reference/html/… – Loydloydie

For the skeptical, the keymap lists this shortcut as, "Compile selected file, package or module". – Bickford

Among all these not working answers, this is the only useful! – Remarque

Answer 2

A solution that uses devTools works :

1 - Adding devtools to your project

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
</dependency>

2 - Enabling automatic build

Open the Settings --> Build-Execution-Deployment --> Compiler and enable :

Build Project Automatically.

3 - Update the value of compiler.automake.allow.when.app.running

press ctrl+shift+A and search for the registry. In the registry, enable :

compiler.automake.allow.when.app.running

---

References :

• https://dzone.com/articles/spring-boot-application-live-reload-hot-swap-with

Restless

Does this not only restart SpringBoot, as when you do it manually? Takes the same amount of time during restart? – Prophylaxis

compiler.automake.allow.when.app.running will restart every time when any file is changed. It took too long time – Deane

I tried this and it did not work for me. Is it perhaps b/c i have multiple maven projects in my Intellij Project? If so, I'm not even sure how to solve that b/c the "Build Project Automatically." setting is seemingly a global Intellij setting – Lucania

The last step (updating compiler.automake.allow.when.app.running) is not needed at least with IntelliJ Ultimate edition. – Verger

The app only restarts when I close the file, and all spring boot is restarted, it's not a true hot reload... am I missing something? I'm using idea Ultimate – Waterproof

The last step is to restart IntelliJ to make it work. – Auxiliaries

In 2019.2 the "Build project automatically" setting have a note "(only works when not running/debugging)". It appears that automatically hotswapping must be enabled in the debug launch configuration. – Couch

Don't forget to disable auto-save – Radmen

@ThorbjørnRavnAndersen where can I enable the hotswapping. I checked the launch configuration, but I did not find it. Is it a launch command parameter or something? – Capone

@Capone open a new question – Couch

In 2021.2 instead of step 3 enable Settings --> Advanced Settings --> Allow auto-make to start even if developed application is currently running – Soldier

Just a helpful note for macOS users. if cmd+shift+a doesn't work, you can try shift+shift which should open the dialog box and there you can search for Registry. – Pointillism

Thanks @Soldier this solved my issue. – Marchand

As of version 2022.2 see Reload modified classes. And for the IntelliJ Ultimate Edition only Spring Boot run configuration → Modify option → On 'Update' action – Scintillator

Answer 3

Step 1: Add developer tools denpendency

Maven

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
    </dependency>
</dependencies>

or ..

Gradle

dependencies {
    compile("org.springframework.boot:spring-boot-devtools")
}

Step 2: Go to File | Settings | Build, Execution, Deployment | Compiler

enable Build project automatically & Apply & OK

Step 3: Press shortcut key Ctrl+Shift+A & Search Registry keyword & Press Enter

Enable compiler.automake.allow.when.app.running & Click Close Button

Step 4: Disable cache on your favorite web browser

Step 5: Done!!!

Watch Solution On YouTube

Aircrewman

If your Action Window close immediately from second time after you typed Registry in Mac version, you could hit Shift button twice to pop the Action Window again. – Turoff

Thank you @shellhub – Spherule

Additionally after 2021.2 version, complier.automake.allow.when.app.running option was moved to Advanced settings. Preferences -> Advanced Settings -> Compiler -> Allow Automake ..... so on... – Tamayo

Couldn't find this in 2021.3.3 CE – Wanhsien

youtrack.jetbrains.com/issue/IDEA-274903/… – Graeae

Answer 4

In my case even after adding the Spring Boot dev tools and checking the build project automatically, it was not working. What was missing was this:

1. Go to the project run configuration.

2. Set on'Update' action and 'On frame deactivation' both to 'Update classes and resources'. And it worked like a charm.

Sunbow

Hi, I cannot find 'Update' and 'On frame deactivation' in my Intellij. Can you help? – Cline

This is exactly why I wrote a comment: I don't see any on 'Update' Action and on Frame Deactivation options when clicking on Run -> Edit Configurations. (I am on Intellij 2018.1.6) – Cline

Could you send a screenshot or a link to it when you click on Edit Configurations? That would make it easier to see what is going on. – Sunbow

@Cline I was having same issue. Unfortunately, the run config been spoken about is for intellij spring-boot support - only available in ultimate edition. – Bugs

@BinaryMonkL: I am working on the Ultimate edition. Do I miss something else? – Cline

@Cline you need to configure it as a spring app and select the spring boot run config from left tab – Bugs

I would go with @BinaryMonkL 's suggestion. You will need to make sure that your project is configured as a Spring App. Did you create this project using Spring Initializr? That is the best way to make sure Intellij brings in tools to support Spring Boot. – Sunbow

Did the trick for me. Is there a way to set this configuration as the default for all projects? – Radmen

Answer 5

Use spring-loaded. It works fine with bean reloading. It's free alternative to JRebel.

Another way is to use DCEVM or hotswapagent

Lame

It's perfect except the Mybatis mapper.xml, after changing myapper.xml's sql code, the reload not work – Deane

Answer 6

I noticed the same problem as well. I am on the Intellij 13.1.1. and for it to hotswap the changed class. I have to run the app in debug mode, then after changing the class, select "Run->Reload Changed Classes" manually.

I also have the debugger set to hotswap as indicated in http://www.jetbrains.com/idea/webhelp/reloading-classes.html but doesn't seem to work.

Anyway, at least the manual "Run->Reload Changed Classes" menu works.

Forty

Answer 7

@Sameer Khanal's answer worked but since so much time has passed, I offer some clarification

1. Install the spring boot devtools dependencies (https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools)

2. Modify your run option

3. Update the options for On 'Update' action and On frame deactivation like so:

4. Click on OK and you are done

Hope that helps

Stichomythia

Works only in ultimate edition. – Wanhsien

Answer 8

For multiple changes, use "Compile And Reload File"(Add "spring-boot-devtools" first). Double click "Shift" to show the diagram in Mac.

Or try spring-loaded which I haven't tried yet. But seems it could work.

Kemp

Answer 9

Add the deployment artifact exploded, in the deployment tab, this did the trick for me.

Loment

Answer 10

You can use either of the following methods to auto reload Thymeleaf templates:

1. Spring Boot Dev Tools
2. Change Thymeleaf Templates Path
3. Gulp Watch

I recommend Gulp watch as it is easier to setup and works great:

var gulp = require('gulp'), 
watch = require('gulp-watch');

gulp.task('watch', function () {
    return watch('src/main/resources/**/*.*', () => {
            gulp.src('src/main/resources/**')
                //replace with build/resources/main/ for netBeans
                .pipe(gulp.dest('out/production/resources/')); 
    });
});

gulp.task('default', ['watch']);

Now enter the following command in your terminal to start gulp watch:

$ gulp 
//OR
$ gulp watch

I wrote a blog post on auto reloading Thymeleaf templates without restart in IntelliJ IDE.

Dinodinoflagellate