Update README.md

johnA1331 · web-flow · commit 53b7b99fa80f · 2020-11-18T17:14:44.000+08:00
diff --git a/core-java-modules/core-java-15/README.md b/core-java-modules/core-java-15/README.md
@@ -4,4 +4,4 @@ This module contains articles about Java 15.
 
 ### Relevant articles
 
-- TODO: add article links here
+- [Sealed Classes and Interfaces in Java 15](https://www.baeldung.com/java-sealed-classes-interfaces)

Original file line number	Diff line number	Diff line change
`@@ -4,4 +4,4 @@ This module contains articles about Java 15.`
`4`	`4`
`5`	`5`	`### Relevant articles`
`6`	`6`
`7`		`-- TODO: add article links here`
	`7`	`+- [Sealed Classes and Interfaces in Java 15](https://www.baeldung.com/java-sealed-classes-interfaces)`