diff --git a/core-java-modules/core-java-string-operations-2/pom.xml b/core-java-modules/core-java-string-operations-2/pom.xml
index 079556712e..a00ae80f13 100644
--- a/core-java-modules/core-java-string-operations-2/pom.xml
+++ b/core-java-modules/core-java-string-operations-2/pom.xml
@@ -64,6 +64,11 @@
             <artifactId>jmh-generator-annprocess</artifactId>
             <version>${jmh-generator.version}</version>
         </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
 
         <dependency>
             <groupId>org.assertj</groupId>
@@ -113,6 +118,7 @@
         <hibernate-validator.version>6.0.2.Final</hibernate-validator.version>
         <javax.el-api.version>3.0.0</javax.el-api.version>
         <javax.el.version>2.2.6</javax.el.version>
+        <commons-codec.version>1.14</commons-codec.version>
     </properties>
 
 </project>
diff --git a/pdf/src/test/java/com/baeldung/pdf/base64/EncodeDecodeUnitTest.java b/core-java-modules/core-java-string-operations-2/src/test/java/com/baeldung/pdf/base64/EncodeDecodeUnitTest.java
similarity index 100%
rename from pdf/src/test/java/com/baeldung/pdf/base64/EncodeDecodeUnitTest.java
rename to core-java-modules/core-java-string-operations-2/src/test/java/com/baeldung/pdf/base64/EncodeDecodeUnitTest.java
diff --git a/pdf/src/test/resources/input.pdf b/core-java-modules/core-java-string-operations-2/src/test/resources/input.pdf
similarity index 100%
rename from pdf/src/test/resources/input.pdf
rename to core-java-modules/core-java-string-operations-2/src/test/resources/input.pdf
diff --git a/pdf/pom.xml b/pdf/pom.xml
index 88836c5ce9..d148aa1670 100644
--- a/pdf/pom.xml
+++ b/pdf/pom.xml
@@ -13,12 +13,6 @@
     </parent>
 
     <dependencies>
-        <dependency>
-            <groupId>commons-codec</groupId>
-            <artifactId>commons-codec</artifactId>
-            <version>${commons-codec.version}</version>
-        </dependency>
-    
         <dependency>
             <groupId>org.apache.pdfbox</groupId>
             <artifactId>pdfbox-tools</artifactId>
@@ -86,7 +80,6 @@
         <poi-scratchpad.version>3.15</poi-scratchpad.version>
         <batik-transcoder.version>1.8</batik-transcoder.version>
         <poi-ooxml.version>3.15</poi-ooxml.version>
-        <commons-codec.version>1.14</commons-codec.version>
     </properties>
 
 </project>