Grails BuildConfig.groovy, difference between build, compile, and runtime?

Question

What's the difference between build, runtime, and compile, in BuildConfig.groovy (1.3.7)

grails.project.dependency.resolution = {

    plugins {
        build "acme:acme-cache:latest.integration"
    }

    dependencies {
        build "com.foo.bar:foobar:1.0.5"       
        runtime "org.apache.httpcomponents:httpclient:4.0.3"
        compile("com.thoughtworks.xstream:xstream:1.3.1")
    }
}

Answer 1

• build - dependency that is only needed by the build process
• runtime - dependency that is needed to run the application, but not compile it e.g. JDBC implementation for specific database vendor. This would not typically be needed at compile-time because code depends only the JDBC API, rather than a specific implementation thereof
• compile - dependency that is needed at both compile-time and runtime. This is the most common case

There are a couple of other dependency scopes:

• test - dependency that is only needed by the tests, e.g. a mocking/testing library
• provided - dependency that is needed at compile-time but should not be packaged with the app (usually because it is provided by the container). An example is the Servlet API