diff --git a/src/main/java/org/tools4j/nobark/loop/Joinable.java b/src/main/java/org/tools4j/nobark/loop/Joinable.java
new file mode 100644
index 0000000..e910892
--- /dev/null
+++ b/src/main/java/org/tools4j/nobark/loop/Joinable.java
@@ -0,0 +1,63 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 nobark (tools4j), Marco Terzer, Anton Anufriev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.tools4j.nobark.loop;
+
+/**
+ * Joinable is a running service such as a thread that can be {@link #join() joined} to await
+ * its termination.
+ */
+@FunctionalInterface
+public interface Joinable {
+    /**
+     * Waits for this Joinable to die.
+     *
+     * <p> An invocation of this method behaves in exactly the same
+     * way as the invocation
+     *
+     * <blockquote>
+     * {@linkplain #join(long) join}{@code (0)}
+     * </blockquote>
+     *
+     * @throws  IllegalStateException
+     *          if any thread has interrupted the current thread
+     * @see Thread#join()
+     */
+    default void join() {
+        join(0);
+    }
+
+    /**
+     * Waits at most {@code millis} milliseconds for this Joinable to
+     * die. A timeout of {@code 0} means to wait forever.
+     *
+     * @param  millis
+     *         the time to wait in milliseconds
+     * @throws  IllegalArgumentException
+     *          if the value of {@code millis} is negative
+     * @throws  IllegalStateException
+     *          if any thread has interrupted the current thread
+     * @see Thread#join(long)
+     */
+    void join(long millis);
+}
diff --git a/src/main/java/org/tools4j/nobark/loop/StoppableThread.java b/src/main/java/org/tools4j/nobark/loop/StoppableThread.java
index 7fe0028..f63c219 100644
--- a/src/main/java/org/tools4j/nobark/loop/StoppableThread.java
+++ b/src/main/java/org/tools4j/nobark/loop/StoppableThread.java
@@ -28,11 +28,13 @@
 
 import sun.misc.Contended;
 
+import static org.tools4j.nobark.loop.RunnableFactory.RunningCondition;
+
 /**
  * A thread that performs a {@link java.lang.Runnable runnable} in a new thread.
  * The thread is started immediately upon construction and it can be stopped via stop or auto-close method.
  */
-public class StoppableThread implements Stoppable {
+public class StoppableThread implements Stoppable, Joinable, RunningCondition {
     private final RunnableFactory runnableFactory;
     private final Thread thread;
     @Contended
@@ -65,10 +67,11 @@ public static StoppableThread start(final RunnableFactory runnableFactory, final
     }
 
     private void run() {
-        final Runnable runnable = runnableFactory.create(this::isRunning);
+        final Runnable runnable = runnableFactory.create(this);
         runnable.run();
     }
 
+    @Override
     public boolean isRunning() {
         return running;
     }
@@ -78,10 +81,7 @@ public void stop() {
         running = false;
     }
 
-    public void join() {
-        join(0);
-    }
-
+    @Override
     public void join(final long millis) {
         try {
             thread.join(millis);