diff --git a/java/org/brotli/wrapper/enc/EncoderJNI.java b/java/org/brotli/wrapper/enc/EncoderJNI.java
index 2f7ef30..888d537 100644
--- a/java/org/brotli/wrapper/enc/EncoderJNI.java
+++ b/java/org/brotli/wrapper/enc/EncoderJNI.java
@@ -35,6 +35,8 @@ class EncoderJNI {
 
     private PreparedDictionaryImpl(ByteBuffer data, ByteBuffer rawData) {
       this.data = data;
+      // Retain a reference to the raw data to prevent it from being garbage collected.
+      this.rawData = rawData;
     }
 
     @Override