<issue_start><issue_comment>Title: Apply retrolambda to custom JavaCompile tasks
username_0: /home/flo/data/code/smack/smack-core/src/main/java/org/jivesoftware/smack/SynchronizationPointWithSmackException.java:130: error: cannot find symbol
        reportFailureSetException(() -> {
                                  ^
  symbol:   method metafactory(Lookup,String,MethodType,MethodType,MethodHandle,MethodType)
  location: interface LambdaMetafactory
1 error
```

it appears that retrolambda is not applied to the `compileAndroid` task.

How do I manually apply it?
<issue_comment>username_1: It's not well documented but to you can create a retrolamda task. Check out the source for the java plugin https://github.com/username_1/gradle-retrolambda/blob/master/gradle-retrolambda/src/main/groovy/me/tatarka/RetrolambdaPluginJava.groovy
<issue_comment>username_0: Thanks for your quick answer. Right now I wonder if I can even achieve what I want to achieve using Retrolambda: Writing Java 8 source code and linking that code against an `android.jar` of the corresponding Android API level. For this it seems to the required that retrolambda compiles the Java 8 source to Java 7 class files with simultaneously using the `android.jar` as boot classpath. But Retrolambda is only able to desugar Java 8 class files to Java 7 class files. Correct?
<issue_comment>username_1: The major problem you'll run into is you need certain java 8 classes on the classpath for retrolambda to work. Have you considered using https://github.com/xvik/gradle-animalsniffer-plugin?
<issue_comment>username_0: AnimalSniffer perfectly solves my use case, Thank you very much for pointing this out.<issue_closed>