how to debug spring application with gradle

For build.gradle.kts file you can also simply use below:

tasks.withType<BootRun> {
    jvmArgs = listOf("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=0.0.0.0:32323")
}

As a response to dankdirkd's answer above: (compare)

gradle bootRun --debug-jvm

will make the gradle build run in debug mode. That probably is not what you want. What you want to achieve is that the springBoot task starts your application in debug mode.

The spring boot task extends the gradle JavaExec task. You can configure the bootRun task in your build.gradle file to add a debug configuration like this:

bootRun {
  jvmArgs=["-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=32323"]
}

For the build.gradle.kts this would look like this (with suspend mode disabled):

tasks {
    val bootRun by getting(BootRun::class) {
        jvmArgs=listOf("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=32323")
    }
}

If your server is within a cloud and you want to debug from local machine, you need to make sure that it allows connections from outside. Use below configuration in that case

tasks {
val bootRun by getting(BootRun::class) {
    jvmArgs=listOf("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=0.0.0.0:32323")
    }
}

Note that the address is now 0.0.0.0:port instead of just port

After you run gradle bootRun --debug-jvm the application is suspended until you connect your debugger to the port it is listening on (port 5005).