gradle构建之后，依赖关系应该怎么办？

Question

I am trying out Gradle, and am wondering, what is supposed to happen to a project's dependencies after you run gradle build ? For example, my sample projects don't run on the command line after they are built, because they are missing dependencies. They seem to compile fine, as gradle doesn't give me errors or warnings about finding the dependencies.

Gradle projects I've made in IntelliJ Idea have the same problem. They compile and run inside the IDE, but are missing dependencies and can't run on the command line.

So what is supposed to happen to the dependencies I declare in the build.gradle file? Shouldn't they be output somewhere together with my .class files? Otherwise, what is the point of gradle when I could manage this by editing my classpath?

Edit: Here is my build.gradle file:

apply plugin: 'java'

jar {
    manifest {
        attributes('Main-Class': 'Animals')
    }
}

repositories {
    flatDir{
        dirs "D:\\libs\\gradleRepo"
    }
}

dependencies {
    compile name: "AnimalTypes-1.0-SNAPSHOT"
}

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

Answer 1

Your Gradle build only takes care of the compile time and allows you to use the specified dependencies in your code (it adds them to the compile classpath). But it does not take care of the runtime. Once the JAR is build, you need to specify the runtime classpath and provide all required dependencies.

You may think, that this is bad or a disadvantage, but actually it is totally fine and intended, because if you build a Java library, you won't need to execute it, you just want to specify it as a dependency for another project. If you would distribute your library to a Maven repository, all dependencies from Maven repositories (module dependencies) would end up in a POM descriptor as transitive dependencies.

Now, if you want to build a runnable Java application, simply use the Gradle Application Plugin ( apply plugin: 'application' ), which will create a ZIP file containing the dependencies and start scripts providing your runtime classpath for execution.

Third-party plugins can also produce so-called fat JARs, which are JAR files with all dependencies included. It depends on your use case if you should use them, because often dependency management via repositories is the better way to go.