diff --git a/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java b/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
index cfc7e69..ac684e7 100644
--- a/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
+++ b/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
@@ -23,5 +23,7 @@
         findViewById(R.id.timer_btn).setOnClickListener(view -> rxProcess.timer());
         findViewById(R.id.error_btn).setOnClickListener(view -> rxProcess.error());
         findViewById(R.id.map_btn).setOnClickListener(view -> rxProcess.map());
+        findViewById(R.id.empty_btn).setOnClickListener(view -> rxProcess.empy());
+        findViewById(R.id.flatmap_btn).setOnClickListener(view -> rxProcess.flatmap());
     }
 }
diff --git a/app/src/main/java/org/ntlab/developrx/JavaRxProcess.java b/app/src/main/java/org/ntlab/developrx/JavaRxProcess.java
index 02d8c3e..aeca684 100644
--- a/app/src/main/java/org/ntlab/developrx/JavaRxProcess.java
+++ b/app/src/main/java/org/ntlab/developrx/JavaRxProcess.java
@@ -182,4 +182,26 @@
                 .map(data -> data.toLowerCase());
         flowable.subscribe(new DebugSubscriber<>());
     }
+
+    /**
+     * からのFlowable/Observableを生成する
+     */
+    public void empy() {
+        Flowable.empty().subscribe(new DebugSubscriber<>());
+    }
+
+    /**
+     * 受け取ったデータをFlowable/Observableに変換し、そのFlowable/Obsevableが持つデータを通知する
+     */
+    public void flatmap() {
+        Flowable<String> flowable = Flowable.just("A", "", "B", "", "C")
+                .flatMap(data -> {
+                    if (data.isEmpty()) {
+                        return Flowable.empty();
+                    } else {
+                        return Flowable.just(data.toUpperCase());
+                    }
+                });
+        flowable.subscribe(new DebugSubscriber<>());
+    }
 }
diff --git a/app/src/main/res/layout/activity_main_java.xml b/app/src/main/res/layout/activity_main_java.xml
index 29157da..9f3b624 100644
--- a/app/src/main/res/layout/activity_main_java.xml
+++ b/app/src/main/res/layout/activity_main_java.xml
@@ -82,6 +82,22 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/error_btn" />
 
+        <Button
+            android:id="@+id/empty_btn"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="empty"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/map_btn" />
+
+        <Button
+            android:id="@+id/flatmap_btn"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="flatmap"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/empty_btn" />
+
     </android.support.constraint.ConstraintLayout>
 
 </ScrollView>