diff --git a/patterns/solid/src/main/java/com/baeldung/s/BadBook.java b/patterns/solid/src/main/java/com/baeldung/s/BadBook.java
index 03c8fcd488..2712314db1 100644
--- a/patterns/solid/src/main/java/com/baeldung/s/BadBook.java
+++ b/patterns/solid/src/main/java/com/baeldung/s/BadBook.java
@@ -10,8 +10,8 @@ public class BadBook {
 
 
   //methods that directly relate to the book properties
-  public String replaceWordInText(String word){
-    return text.replaceAll(word, text);
+  public String replaceWordInText(String word, String replacementWord){
+    return text.replaceAll(word, replacementWord);
   }
 
   public boolean isWordInText(String word){
diff --git a/patterns/solid/src/main/java/com/baeldung/s/GoodBook.java b/patterns/solid/src/main/java/com/baeldung/s/GoodBook.java
index b0993aca2b..04606bcdcd 100644
--- a/patterns/solid/src/main/java/com/baeldung/s/GoodBook.java
+++ b/patterns/solid/src/main/java/com/baeldung/s/GoodBook.java
@@ -9,8 +9,8 @@ public class GoodBook {
   //constructor, getters and setters
 
   //methods that directly relate to the book properties
-  public String replaceWordInText(String word){
-    return text.replaceAll(word, text);
+  public String replaceWordInText(String word, String replacementWord){
+    return text.replaceAll(word, replacementWord);
   }
 
   public boolean isWordInText(String word){