我正在使用gradle构建工具，但我无法获得spark core的源代码和文档。我已经搜索并申请了：

idea {
    project {
        jdkName = '1.8'
        languageLevel = '1.8'
    }
    module {
        downloadJavadoc = true
        downloadSources = true
    }
}

但对我来说还是不行。我想我遗漏了一些东西，比如重建整个项目或者下载这些东西。
我申请了 ./gradlew cleanIdea idea 也。
当我试着在sparkconf.class上用pressed命令单击时，我按 Download Sources 我明白了 Sources not found for: org.apache.spark:spark-core_2.12:2.4.5 以及“运行”选项卡的结果：

21:11:29: Executing task 'DownloadSources'...

:DownloadSources FAILED

BUILD FAILED

Total time: 0.124 secs

FAILURE: Build failed with an exception.

* Where:

Initialization script '/private/var/folders/06/97bzw1l51r59l65thfzs7hd80000gn/T/ijmiscinit1.gradle' line: 14

* What went wrong:

Execution failed for task ':DownloadSources'.
> Could not resolve all dependencies for configuration ':downloadSourcesFrom_MavenRepo_91653a2f-0439-4794-b77a-3812f9926728'.
   > java.lang.NullPointerException (no error message)

* Try:

Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
21:11:29: Task execution finished 'DownloadSources'.

下面是两个相当长的任务输出：
下载源--信息：https://pastebin.com/d07jmgxt
downloadsources--堆栈跟踪：https://pastebin.com/6cekhwrk
idea.log文件https://pastebin.com/eqcdxpwb
最新的公共intellij版本：2020.1.1通过工具箱安装最新的macos:10.15.4 java 1.8 jdk-8u251-macosx-x64.dmg，从oracle.com下载
你能帮我弄明白我该怎么做才能修好它吗？