diff --git a/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java b/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
index bd93bbe..bce174b 100644
--- a/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
+++ b/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
@@ -19,5 +19,6 @@
         findViewById(R.id.just_btn).setOnClickListener(view -> rxProcess.just());
         findViewById(R.id.fromarray_btn).setOnClickListener(view -> rxProcess.fromArray());
         findViewById(R.id.range_btn).setOnClickListener(view -> rxProcess.range());
+        findViewById(R.id.interval_btn).setOnClickListener(view -> rxProcess.interval());
     }
 }