diff --git a/java/src/main/java/kanzi/transform/BWTBlockCodec.java b/java/src/main/java/kanzi/transform/BWTBlockCodec.java
index b1fd898d..99767fd2 100644
--- a/java/src/main/java/kanzi/transform/BWTBlockCodec.java
+++ b/java/src/main/java/kanzi/transform/BWTBlockCodec.java
@@ -119,7 +119,7 @@ public boolean inverse(SliceByteArray input, SliceByteArray output)
       if (input.array == output.array)
          return false;
 
-      int blockSize = input.length;
+      final int blockSize = input.length;
 
       if (this.bsVersion > 5)
       {
@@ -157,7 +157,7 @@ public boolean inverse(SliceByteArray input, SliceByteArray output)
                   return false;
           }
 
-          blockSize -= headerSize;
+          input.length = blockSize - headerSize;
       }
       else
       {