diff --git a/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java b/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java
index f94c82b7215..c583c2708ac 100644
--- a/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java
+++ b/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java
@@ -97,7 +97,7 @@ protected boolean removeEldestEntry(Map.Entry<Sha256Hash, Object> entry) {
     // Used to stop other applications/processes from opening the store.
     protected FileLock fileLock = null;
     protected RandomAccessFile randomAccessFile = null;
-    private FileChannel channel;
+    private final FileChannel channel;
     private int fileLength;
 
     /**