diff --git a/src/main/java/lambdasinaction/chap7/ForkJoinSumCalculator.java b/src/main/java/lambdasinaction/chap7/ForkJoinSumCalculator.java
index 8f74a90a..616018fa 100644
--- a/src/main/java/lambdasinaction/chap7/ForkJoinSumCalculator.java
+++ b/src/main/java/lambdasinaction/chap7/ForkJoinSumCalculator.java
@@ -8,7 +8,7 @@
 
 public class ForkJoinSumCalculator extends RecursiveTask<Long> {
 
-    public static final long THRESHOLD = 10_000;
+    private static final long THRESHOLD = 10_000;
 
     private final long[] numbers;
     private final int start;