How to access `java.home` being used by Gradle?
<p><code>./gradlew properties</code> shows no properties having the value of <code>${JAVA_HOME}</code> and the following emit an error indicating no such property exists:</p>

<pre><code>println org.gradle.java.home
println gradle.java.home
println java.home
</code></pre>

<p>In the end, I want to specify a compile-time dependency on the <code>tools.jar</code> that's part of the JDK. For example:</p>

<pre><code>dependencies {
  compile files("${java.home}/lib/tools.jar")
}
</code></pre>