diff --git a/spring-test/src/main/java/org/springframework/test/web/servlet/result/JsonPathResultMatchers.java b/spring-test/src/main/java/org/springframework/test/web/servlet/result/JsonPathResultMatchers.java
index 48ff721ef1..fe33f1073d 100644
--- a/spring-test/src/main/java/org/springframework/test/web/servlet/result/JsonPathResultMatchers.java
+++ b/spring-test/src/main/java/org/springframework/test/web/servlet/result/JsonPathResultMatchers.java
@@ -260,7 +260,7 @@ public class JsonPathResultMatchers {
 				return content.substring(this.prefix.length());
 			}
 			catch (StringIndexOutOfBoundsException ex) {
-				throw new AssertionError("JSON prefix \"" + this.prefix + "\" not found", ex);
+				throw new AssertionError("JSON prefix \"" + this.prefix + "\" not found: " + ex);
 			}
 		}
 		else {