diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContactId.java b/bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContactId.java
index a0a7c7f40..535f8f531 100644
--- a/bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContactId.java
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContactId.java
@@ -3,6 +3,7 @@ package org.briarproject.bramble.api.contact;
 import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -18,7 +19,7 @@ public class PendingContactId extends UniqueId {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 		return o instanceof PendingContactId && super.equals(o);
 	}
 }