SLING-5644 Provide an messaging implementation based on Commons Email

wrap ThreadPool in Executor to stick with Commons Threads 3.2.6

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1738327 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 73b0583..8c68c6d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -165,7 +165,7 @@
     <dependency>
       <groupId>org.apache.sling</groupId>
       <artifactId>org.apache.sling.commons.threads</artifactId>
-      <version>3.2.7-SNAPSHOT</version>
+      <version>3.2.6</version>
       <scope>provided</scope>
     </dependency>
     <dependency>
diff --git a/src/main/java/org/apache/sling/commons/messaging/mail/internal/SimpleMailService.java b/src/main/java/org/apache/sling/commons/messaging/mail/internal/SimpleMailService.java
index 19d003f..9a487f6 100644
--- a/src/main/java/org/apache/sling/commons/messaging/mail/internal/SimpleMailService.java
+++ b/src/main/java/org/apache/sling/commons/messaging/mail/internal/SimpleMailService.java
@@ -114,7 +114,7 @@
 
     @Override
     public CompletableFuture<Result> send(@Nonnull final String message, @Nonnull final String recipient, @Nonnull final Map data) {
-        return CompletableFuture.supplyAsync(() -> sendMail(message, recipient, data, mailBuilder), threadPool);
+        return CompletableFuture.supplyAsync(() -> sendMail(message, recipient, data, mailBuilder), runnable -> threadPool.submit(runnable));
     }
 
     private MailResult sendMail(final String message, final String recipient, final Map data, final MailBuilder mailBuilder) {