Jackson dependency: NoClassDefFoundError

Plugins Plugin Development
1

I have added the following to my gradle dependencies:

compile "com.fasterxml.jackson.core:jackson-core:2.7.0"; compile "com.fasterxml.jackson.core:jackson-annotations:2.7.0"; compile "com.fasterxml.jackson.core:jackson-databind:2.7.0";

But when I use Jackson classes, NoClassDefFoundError is being thrown, when the plugin is run.

2

Is Jackson already included in Sponge? If not you’ll need to include it in your jar file.

3

Is there a way to do this with gradle (so that it’s always up to date)?

4

You can include a dependency within your JarFile like so:

Add

configurations {
    shadow
    compile.extendsFrom shadow
}

To your build.gradle (somewhere before the dependencies block)

Add

jar {
    configurations.shadow.each { slice ->
        from(project.zipTree(slice)) {
        }
    }
}

To your build.gradle, or if the ‘jar’ block already exists, just add the configuration in the one above.

You should then be able to declare a dependency like so: “shadow ‘some-dependency’” and it should be included in your jar…

Please note, depending on the license of a project, redistribution is illegal, however Jackson is under the Apache 2 license, so your good.

5

How do I fix “Could not find property ‘shadow’ on configuration container.”?

6

Did you name it configuration instead of configurations? (just a guess)
otherwise, show your build.gradle

7 
    group 'MCore'
    version '1.0-SNAPSHOT'

    apply plugin: 'java'

    version = '1.0'

    repositories {
        mavenCentral()
        maven { url 'http://repo.spongepowered.org/maven' }
        maven { url 'http://repo1.maven.org/maven2'}
    }


    sourceSets {
        main {
            java {
                srcDirs = ['MCore/src/main/java']
            }
        }

        test {
            java {
                srcDirs = ['MCore/src/main/java']
            }
        }
    }

    jar {
        configurations.shadow.each { slice ->
            from(project.zipTree(slice)) {
            }
        }
    }

    configurations {
        shadow
        compile.extendsFrom shadow
    }

    dependencies {
        compile "org.spongepowered:spongeapi:3.0.0";
        compile "shadow 'com.fasterxml.jackson.core:jackson-core:2.7.0'";
        compile "shadow 'com.fasterxml.jackson.core:jackson-annotations:2.7.0'";
        compile "shadow 'com.fasterxml.jackson.core:jackson-databind:2.7.0'";
    }
8

The configurations block should be above where it’s referenced. Put it above jar section.

Not quite, try this:

    compile "org.spongepowered:spongeapi:3.0.0"
    shadow "com.fasterxml.jackson.core:jackson-core:2.7.0"
    shadow "com.fasterxml.jackson.core:jackson-annotations:2.7.0"
    shadow "com.fasterxml.jackson.core:jackson-databind:2.7.0"
9

OK. Now I put it like this:

    configurations {
        shadow
        compile.extendsFrom shadow
    }
    dependencies {
        compile "org.spongepowered:spongeapi:3.0.0";
        shadow "com.fasterxml.jackson.core:jackson-core:2.7.0";
        shadow "com.fasterxml.jackson.core:jackson-annotations:2.7.0";
        shadow "com.fasterxml.jackson.core:jackson-databind:2.7.0";
    }
    jar {
        configurations.shadow.each { slice ->
            from(project.zipTree(slice)) {
            }
        }
    }

But NoClassDefFoundError is still thrown.

10

Don’t you need to include the gradle shadow plugin?

But anyway, I thought if you where shadowing jar’s it was good practice to rename them so you don’t conflict with others using the library?

11

I found a solution for my original problem using Gson.

12

Me too, GSON is so much simpler than everything.