diff --git a/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java b/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
index e5cdaab..585d373 100644
--- a/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
+++ b/app/src/main/java/org/ntlab/developrx/JavaMainActivity.java
@@ -21,5 +21,6 @@
         findViewById(R.id.range_btn).setOnClickListener(view -> rxProcess.range());
         findViewById(R.id.interval_btn).setOnClickListener(view -> rxProcess.interval());
         findViewById(R.id.timer_btn).setOnClickListener(view -> rxProcess.timer());
+        findViewById(R.id.error_btn).setOnClickListener(view -> rxProcess.error());
     }
 }