Hello there, I am writing a ci script and I want to be able to control the file name of the jar that gets created when

gradlew bootJar

is executed from the terminal. Is there a flag associated with the

bootJar

task that can allow me to change the filename? I know it can done by configuring the

build.gradle

file but that's not what I am looking for.

You mean a commandline flag? Probably not, but just check it

./gradlew help --task bootJar

. If not, you could have an init script that makes the necessary changes and include that using

-I

.

hmm....that command shows only a single option to "rerun". Ok, so my real need is that I am building a spring boot application inside a dockerfile and I want the jar file to be the same name no matter the

version

in

build.gradle

.

Set

version

on

bootJar

to

null

I guess

Hmm..I really dont want to have a static configuration to name the bootjar as I would not want people trying to build locally facing issues. I guess I can backup the

build.gradle

file edit it with sed right before I build and restore the backup after build. Seems very hacky...

perhaps rename the jar as you move it to your container.

@Chris Lee The jar is getting built in the container (multistaged)

sure, simply rename it once built.

Getting to know the name that it got built with is the challenge here. I can do some bash stuff to get the jar name but I was looking if there was some functionality in gradle itself to get it.

mv build/libs/<name>-*.jar <dest>/<name>.jar

or somesuch will do it (<name> is generally the known project name, the wildcard handles the version), if you’re not able to modify the build script accordingly.

As I said, writing bash is not a challenge for me and that's not what I am asking help for. Its getting the value of <name> right after build, without needing to grep the build.gradle.

if you are building a known project,

<name>

is a well-known value, generally the project name. Is there some additional unstated requirement preventing using that well known name?

I would know the name beforehand and it would be static, true, but the jar gets suffixed with the version which isn't static, and I would need to grep the build.gradle file to get that value first

No, as noted just wildcard the variable portion:

mv build/libs/<name>-*.jar <dest>/<name>.jar

Hmmm, now that I think about it, that certainly solves my problem the first way. Its not like a single bootrun will create multiples of a jar with the same name and different versions

you can check what is created and adjust the wildcard/glob pattern accordingly.

Hmm, that's certainly one way. I was hoping that gradle would help be somehow so that I don't have to run any scripts, but this is pretty much a one liner and can't get better than that. Thank you for the ideas. I will work on this tomorrow, back to bed for me 🙏

I already told you how to do it with Gradle. Write an init script that sets the

version

property of the

bootJar

task to

null

and use it with

-I

parameter or by putting it to

~/.gradle/init.d/

.

@Vampire ah sorry, I forgot to mention that I was having issues doing that with an init script. I have tried a few ways but neither of them works. Here's a few scripts I have tried:

bootJar {
    version = null
}

Gives the error:

Could not find method bootJar() for arguments [init_4dts4ab5klk4h2jow1p9qaoa7$_run_closure1@557b2fb0] on build of type org.gradle.invocation.DefaultGradle.

gradle.projectsEvaluated {
    bootJar {
        version = null
    }
}

Same error as above

gradle.allprojects {
    task bootJar {
        version = null
    }
}

Gives the error:

Cannot add task 'bootJar' as a task with that name already exists.

This one is due to

build.gradle

also creating that task, so I wrote the next one

gradle.projectsEvaluated {
    tasks.whenTaskAdded { task ->
        if (task.name == 'bootJar') {
            project.version = null
        }
    }
}

Gives the error:

Could not get unknown property 'tasks' for build

. So next I tried using

allprojects

instead and that builds but doesn't change the jar name. Sorry for the wall of text but I am at a loss here. I would love to use a gradle way of doing this still but I just cant seem to figure out the correct script.

If course setting the project version does not work and might even break other things.

BootJar

is a subclass of

Jar

, so the property you want to set is

archiveVersion

. And don't use

whenTaskAdded

, that completely breaks task configuration avoidance. Use

tasks.named { it == "bootJar" }.configureEach { ... }

.

Hmm...I am really sorry but things are just not working. I tried

gradle.projectsEvaluated {
    tasks.named { it == "bootJar" }.configureEach {
        archiveFileName.set("my.jar")
    }
}

and

tasks.named { it == "bootJar" }.configureEach {
    it.archiveFileName.set("my.jar")
}

They are all giving me the error

Could not get unknown property 'tasks' for build of type org.gradle.invocation.DefaultGradle.

Instead doing

gradle.allprojects {
    tasks.named { it == "bootJar" }.configureEach {
        archiveFileName.set("my.jar")
    }
}

is giving the error

No signature of method: org.gradle.api.internal.tasks.DefaultTaskContainer.named() is applicable for argument types

. So, I tried doing

gradle.allprojects {
    tasks.named ("bootJar").configureEach {
        archiveFileName.set("my.jar")
    }
}

which gives me

Task with name 'bootJar' not found in root project

. Honestly, I have no idea what I am doing wrong...

tasks.named { ... }

works lazy,

tasks.named(...)

not. But

tasks.named { ... }

is pretty young. If it complains that it does not exist, your Gradle version is too old. Either use a recent Gradle version, or alternatively use

tasks.matching { it.name == "bootJar" }.configureEach { ... }

Great! That works! My current project is on 7.6.1 so I guess its too old for that. Thank you for helping me get to the bottom of this. Much appreciate the help by you both