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Run an Application

How to run a project in IntelliJ IDEA.

This page describes how to run a project with IntelliJ IDEA.

Run a Spring Boot Project

Spring Boot makes it easier to run a Java web application because it takes care of starting and configuring the server.

To run your application, all you need to do is to run the Application class that contains the main() method that starts Spring Boot. IntelliJ automatically detects that you have an Application class with a main() method and displays it in the run configurations drop-down.

To start the application, either:

  • Click the "play" button next to the "run configurations" drop-down.

  • Open Application.java and click the "play" button next to the code line containing the main() method.

Run button locations

The first time you start a Vaadin application, it downloads frontend dependencies and builds a JavaScript bundle. This can take several minutes, depending on your computer and internet speed.

You know that your application has started when you see the following output in the console:

Tomcat started on port(s): 8080 (http) with context path ''
Started Application in 80.189 seconds (JVM running for 83.42)

You should now be able to open the web application at localhost:8080.

Run Maven Goals

You can use Maven to compile and run a Vaadin application. IntelliJ IDEA has an excellent integration with Maven. You can run common commands such as mvn install without having to leave the IDE.

You can run the application in a development server with Maven goals such as jetty:run (plain Java), tomee:run (Java EE and CDI), or spring-boot:run (Spring Boot). With Spring Boot, you can run the Application class, as described in Run a Spring Boot Project.

  • Open the Maven view by clicking the vertical tab on the right side of the IntelliJ IDEA window:

    Maven projects view
    Maven Projects View

    This view shows all the available Maven projects and their build phases and build goals.

  • If you want to run mvn install, expand the project tree in the Maven view to show the corresponding lifecycle phase.

    Lifecycle phases

  • Double-click install.

You can see how IntelliJ IDEA executes the install build phase. First, it executes all the previous phases in Maven’s default lifecycle. Finally, in the install phase, it downloads dependencies and copies the generated artifacts into your local Maven repository, among other things.

You can use a similar approach to run any Maven goal. For example, you can double-click the jetty:run goal in the Plugins sub-tree to deploy and run the web application implemented in the project you imported. Similarly, if you are using Spring Boot, you can double-click spring-boot:run to run the application.

To learn more about the topics covered here:

Create a Run Configuration

Since using a goal to run the application could be a frequent task during the development, you may want to create a run configuration for it.

A run configuration is a shortcut to run a specific task from within the IDE. In the following, you create a run configuration for the jetty:run Maven goal to make it simpler to run the web application.

  • Open the Maven view.

  • Right-click the jetty:run, tomee:run, or spring-boot:run item under the appropriate folder.

    Technology Stack Embedded Server Goal to Run

    Spring Boot

    –

    spring-boot:run

    CDI / Java EE

    Apache TomEE

    tomee:run

    Plain Java

    Jetty

    jetty:run

  • Select Create webapp [jetty:run] (or tomee:run or spring-boot:run):

    Create running configuration option

  • For simplicity, change the name of the configuration to Run on Jetty (or TomEE or Spring Boot)

    Run on Jetty

  • Click OK:

You should see the new option in the top-right corner of IntelliJ IDEA:

Running configuration created

Now you can deploy and run the web application by clicking the "run" (or "debug") icon in the toolbar:

Run icon

Redeployment during Development

If you edit and save any of the source files, they are compiled automatically, but you can only see the changes by restarting the server. In the Run panel, click the "rerun" icon, or press Ctrl+5 in the editor. You can then refresh the page to use the updated version.

Live Reload should be enabled by default, making the page refresh automatically.

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