Intellij slowish compiles

The output prints the full cycle of the build. The incremental build IDE feature requires collecting the dependencies information and some analysis. In medium and big projects it significantly decreases subsequent build times after the project has been fully built. Btw, the fact that there is Ant task execution phase does not mean that IDE actually executes Ant tasks. It is just a status message of the phase IDE builder passes.

As for the 2.5 seconds time of the build - need to investigate each case individually. For example what plugins are installed in IDE, what is the project configuration, environment etc. You can try disabling all plugins for the technologies you do not use, including Kotlin plugin if you do not use Kotlin - it might improve the build speed.

Thx for your answer. I was hesitant to ask about this, because i assumed it indeed is one of my settings or plugins that might be messing things up. However the 2nd computer i tested on, was a completely fresh install of windows and hardly had anything on it. I tried both 2020, 2021 (eval ultimate and community ed) and all of them behaved the same. Default plugins etc. 

(I try not to be unfair in my expectations and i fully understand intellij is way more advanced then many IDE's, which always comes at a price of course.)

I searched for "incremental" to disable incremental build to see if that helps (since you mention it), but the feature is only for scala and kotlin and not java? (q1)

Although i totally not expected anything to change, i did install a much newer 17 jdk from here: https://adoptium.net/?variant=openjdk17&jvmVariant=hotspot

Strangely enough my build process looks a bit different now and much snapier (400ms)

Executing task ':classes'...

> Task :compileJava UP-TO-DATE
> Task :processResources NO-SOURCE
> Task :classes UP-TO-DATE

Is it now doing a different build task, since its much quicker and show completely different lines then before? What did i do to trigger this? Can this be cause by a plugin (q2)

Where are the build-process defined anyway. I did a couple of full searches on key phrases (including binary files) on the install dir of intellij but nothing showed up. (q3)

Its not just about speed, its also about understanding what it actually tries to do. In the modern era,  2.5 sec is a long time for a single java file on 4000MB/s nvme's and 6core intels with 32GB ram. 

When im back home ill try your suggestions and disable kotlin plugins and whatever i feel like might influence it. I dont use kotlin myself (one of the few languages i never touched, but by build script is using a "build.gradle.kts" so i think it needs kotlin for gradle?

You might be wondering why i want intellij to build the java if it has a gradle task... It used to be that native task build a bit faster then using the gradle build, but more importantly, when i run the task "Run" in gradle, it runs properly but never stops when "Terminating" it until i use windows taskmanager. Even after i close intellij it still runs. Also "rerun" doesnt work, and it states the destination port is in used (which makes sense if the old process hangs). When i try to debug button, it never triggers on the breakpoints, so using intellij build seemed a good alternative since it does close the process and does allow debugging.

edit: to be clear, the real project has a gradle build file, but the tests i did after (to pinpoint the cause) were done with freshly created projects from the intellij helloworld template java app. I created a fresh project about 10 times to makes sure its "clean". 

edit2 I should have mentioned it before, but the only way i could find in intellij to build/run the java app is by using the the template from Run/debug configurations called "Application". It has many templates but nothing else seemed fitting for it. I would expect to see some barebones "java build&run" template there but application seemed the only one fitting. Maybe there is a better way ? (q4)

>Strangely enough my build process looks a bit different now and much snapier (400ms)

This is the build from Gradle. Looks like you ahve opened a Gradle project? In such a case IDE by default delegate the build actions to Gradle. You can change the behaviour in Settings (Preferences on macOS) | Build, Execution, Deployment | Build Tools | Gradle | Build and run using.

Incremental build is always used by IDE and cannot be disabled. It works for Java as well.

Thx for your answer. In the [Build tools] > [Gradle] i indeed had set it before to use intellij as the compiler but apparently it snapped back (or maybe i did it myself during all testing) .

I understand you can't elaborate on all questions i had before, but let me stick to the core issue. If i understand you correctly, even the most basic helloworld.java application build by intellij will always do all "incremental build" steps and there is nothing that can be done to make the build process more bare bones. That this will take 2.5 sec on a clean windows with bulky hardware and clean intellij is by design and regarded as acceptable? 

If this is correct it is at least clear why this happens. I noticed other people also wondering about this during my google searching. If i have some time ill try to investigate why the gradle run task cant be terminated from within intellij and doesn't debug out of the box either, because it suddenly became more attractive to use. 

>will always do all "incremental build" steps and there is nothing that can be done to make the build process more bare bones. 

Yes IDE needs all the phases to be executed. Please try disabling plugins for the technologies you do not use to make the build process faster. Disabling Kotlin plugin should help to make time less.

>If i have some time ill try to investigate why the gradle run task cant be terminated from within intellij and doesn't debug out of the box either, because it suddenly became more attractive to use. 

Task termination and debugging is working fine for me. Please add more details and the steps about the problem.