One of the biggest advantages of packaging your application as a jar and using an embedded HTTP server is that you can run your application as you would any other. The sample applies to debugging Spring Boot applications. You do not need any special IDE plugins or extensions.
![]() | Note |
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This section only covers jar based packaging. If you choose to package your application as a war file, you should refer to your server and IDE documentation. |
You can run a Spring Boot application from your IDE as a Java application.
However, you first need to import your project.
Import steps vary depending on your IDE and build system.
Most IDEs can import Maven projects directly.
For example, Eclipse users can select Import…
→ Existing Maven Projects
from the File
menu.
If you cannot directly import your project into your IDE, you may be able to generate IDE metadata by using a build plugin. Maven includes plugins for Eclipse and IDEA. Gradle offers plugins for various IDEs.
![]() | Tip |
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If you accidentally run a web application twice, you see a “Port already in use” error.
STS users can use the |
If you use the Spring Boot Maven or Gradle plugins to create an executable jar, you can run your application using java -jar
, as shown in the following example:
$ java -jar target/myapplication-0.0.1-SNAPSHOT.jar
It is also possible to run a packaged application with remote debugging support enabled. Doing so lets you attach a debugger to your packaged application, as shown in the following example:
$ java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=8000,suspend=n \ -jar target/myapplication-0.0.1-SNAPSHOT.jar
The Spring Boot Maven plugin includes a run
goal that can be used to quickly compile and run your application.
Applications run in an exploded form, as they do in your IDE.
The following example shows a typical Maven command to run a Spring Boot application:
$ mvn spring-boot:run
You might also want to use the MAVEN_OPTS
operating system environment variable, as shown in the following example:
$ export MAVEN_OPTS=-Xmx1024m
The Spring Boot Gradle plugin also includes a bootRun
task that can be used to run your application in an exploded form.
The bootRun
task is added whenever you apply the org.springframework.boot
and java
plugins and is shown in the following example:
$ gradle bootRun
You might also want to use the JAVA_OPTS
operating system environment variable, as shown in the following example:
$ export JAVA_OPTS=-Xmx1024m
Since Spring Boot applications are plain Java applications, JVM hot-swapping should work out of the box. JVM hot swapping is somewhat limited with the bytecode that it can replace. For a more complete solution, JRebel can be used.
The spring-boot-devtools
module also includes support for quick application restarts.
See the Chapter 21, Developer Tools section later in this chapter and the Hot swapping “How-to” for details.