Deprecate CSB as we can use JDK utils instead.
diff --git a/core/camel-util/src/main/java/org/apache/camel/util/CollectionStringBuffer.java b/core/camel-util/src/main/java/org/apache/camel/util/CollectionStringBuffer.java
index eb3bbcf..470b25b 100644
--- a/core/camel-util/src/main/java/org/apache/camel/util/CollectionStringBuffer.java
+++ b/core/camel-util/src/main/java/org/apache/camel/util/CollectionStringBuffer.java
@@ -18,7 +18,10 @@
 
 /**
  * A little helper class for converting a collection of values to a (usually comma separated) string.
+ *
+ * @deprecated use JDK {@link String#join(CharSequence, CharSequence...)} or {@link java.util.StringJoiner}.
  */
+@Deprecated
 public class CollectionStringBuffer {
     private final StringBuilder buffer = new StringBuilder();
     private String separator;