Gradle build fails thanks to 'fatJar task' although code worked for me in another project

Question

I tried to create a fatJar with Gradle. I found a good example on this site that worked well for me in another project. In my recent project an error occurs during the 'gradlew build' task, namely the following:

FAILURE: Build failed with an exception.

Where: Build file 'D:\dev\MarkPublished\build.gradle' line: 40

What went wrong: A problem occurred evaluating root project 'markpublished'. Could not find method Attributes() for arguments [{Implementation->Title=Gradle Jar File, Implementation-Version=1.0-Snapshot, Main-Class=path.classname}] on root project 'myproject'.

This is my (shortened) 'build.gradle'-file:

plugins {
  id 'java'
  id 'idea'
}

group 'mygroup'
version '1.0-Snapshot'

sourceCompatibility = 1.8
targetCompatibility = 1.8

idea {
    ...
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.4'
}

repositories {
    ...
}

dependencies {
    ...
}

task fatJar(type: Jar) {
    manifest {
        Attributes ('Implementation-Title': 'Gradle Jar File',
                'Implementation-Version': version,
                'Main-Class': 'path.classname')
    }
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    with Jar
}

I use Win7 and IntelliJ Idea 14.1.5.

Honestly, I absolutely have no clue and I wouldn't ask here if it didn't already work for me in another project.

Answer 1

Try to make a fatJar task as:

task fatJar(type: Jar) {
    manifest {
        attributes 'Implementation-Title': 'Gradle Jar File',
                   'Implementation-Version': version,
                   'Main-Class': 'path.classname'
    }
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
    with Jar
}

Attributes must be in lowercase, like attributes.