是什么build/install/gradleHelloWorld-shadow？该目录中应该或不应该是什么？
最简单的“hello world”无法构建：
thufir@dur:~/NetBeansProjects/gradleHelloWorld$
thufir@dur:~/NetBeansProjects/gradleHelloWorld$ gradle clean runShadow
> Task :shadowJar
A problem was found with the configuration of task ':shadowJar'. Registering invalid inputs and outputs via TaskInputs and TaskOutputs methods has been deprecated and is scheduled to be removed in Gradle 5.0.
- No value has been specified for property 'mainClassName'.
The SimpleWorkResult type has been deprecated and is scheduled to be removed in Gradle 5.0. Please use WorkResults.didWork() instead.
> Task :startShadowScripts
Using TaskInputs.file() with something that doesn't resolve to a File object has been deprecated and is scheduled to be removed in Gradle 5.0. Use TaskInputs.files() instead.
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':installShadowDist'.
> The specified installation directory '/home/thufir/NetBeansProjects/gradleHelloWorld/build/install/gradleHelloWorld-shadow' is neither empty nor does it contain an installation for 'gradleHelloWorld'.
If you really want to install to this directory, delete it and run the install task again.
Alternatively, choose a different installation directory.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
* Get more help at https://help.gradle.org
BUILD FAILED in 1s
5 actionable tasks: 5 executed
Publishing build scan...
https://gradle.com/s/t7jbmhjz23giw
thufir@dur:~/NetBeansProjects/gradleHelloWorld$
构建文件：
plugins {
id 'com.gradle.build-scan' version '1.8'
id 'java'
id 'application'
id 'com.github.johnrengelman.shadow' version '2.0.1'
}
buildScan {
licenseAgreementUrl = 'https://gradle.com/terms-of-service'
licenseAgree = 'yes'
publishAlways()
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
mainClassName = 'net.bounceme.dur.gradle.hello.App'
shadowJar {
baseName = 'greeter'
classifier = null
version = null
}
repositories {
jcenter()
}
configurations {
provided
}
dependencies {
}
中止后的项目runShadow：
thufir@dur:~/NetBeansProjects/gradleHelloWorld$
thufir@dur:~/NetBeansProjects/gradleHelloWorld$ tree
.
├── build
│ ├── classes
│ │ └── java
│ │ └── main
│ │ └── net
│ │ └── bounceme
│ │ └── dur
│ │ └── gradle
│ │ └── hello
│ │ └── App.class
│ ├── install
│ │ └── gradleHelloWorld-shadow
│ ├── libs
│ │ └── greeter.jar
│ ├── scriptsShadow
│ │ ├── gradleHelloWorld
│ │ └── gradleHelloWorld.bat
│ └── tmp
│ ├── compileJava
│ └── shadowJar
│ └── MANIFEST.MF
├── build.gradle
├── gradle
│ └── wrapper
│ ├── gradle-wrapper.jar
│ └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── src
├── main
│ └── java
│ ├── dur
│ └── net
│ └── bounceme
│ └── dur
│ └── gradle
│ └── hello
│ └── App.java
└── test
└── java
29 directories, 12 files
thufir@dur:~/NetBeansProjects/gradleHelloWorld$
有问题的/home/thufir/NetBeansProjects/gradleHelloWorld/build/install/gradleHelloWorld-shadow目录被 clean 删除，确定 gradle 正在构建这个目录。
刚刚升级了gradle：
thufir@dur:~$
thufir@dur:~$ sdk ls gradle
==== INTERNET NOT REACHABLE! ===================================================
Some functionality is disabled or only partially available.
If this persists, please enable the offline mode:
$ sdk offline
================================================================================
--------------------------------------------------------------------------------
Offline: only showing installed gradle versions
--------------------------------------------------------------------------------
> 4.3.1
* 4.2.1
--------------------------------------------------------------------------------
* - installed
> - currently in use
--------------------------------------------------------------------------------
thufir@dur:~$
（Wi-Fi 可能有点不稳定。）