diff --git a/jdk/test/java/nio/Buffer/Chars.java b/jdk/test/java/nio/Buffer/Chars.java
index e91b6a73883..ef2df66ac14 100644
--- a/jdk/test/java/nio/Buffer/Chars.java
+++ b/jdk/test/java/nio/Buffer/Chars.java
@@ -51,8 +51,8 @@ public class Chars {
      */
     static CharBuffer randomizeRange(CharBuffer cb) {
         int mid = cb.capacity() >>> 1;
-        int start = RAND.nextInt(mid);
-        int end = mid + RAND.nextInt(mid);
+        int start = RAND.nextInt(mid + 1); // from 0 to mid
+        int end = mid + RAND.nextInt(cb.capacity() - mid + 1); // from mid to capacity
         cb.position(start);
         cb.limit(end);
         return cb;