diff --git a/src/main/java/info/augendre/caps_extractor/MainPanel.java b/src/main/java/info/augendre/caps_extractor/MainPanel.java
index 8aff1d1..c531c83 100644
--- a/src/main/java/info/augendre/caps_extractor/MainPanel.java
+++ b/src/main/java/info/augendre/caps_extractor/MainPanel.java
@@ -50,6 +50,11 @@ public class MainPanel {
         });
     }
 
+    /**
+     * Extracts the upper case characters from the given string.
+     * @param s The string where to extract upper case characters.
+     * @return The upper case characters found in the given string.
+     */
     public String extractUpperCase(String s) {
         String upperCase = "";
         for (int i = 0; i < s.length(); i++) {