diff --git a/core-java-modules/core-java-io/pom.xml b/core-java-modules/core-java-io/pom.xml
index faeddafd81..caf9fca756 100644
--- a/core-java-modules/core-java-io/pom.xml
+++ b/core-java-modules/core-java-io/pom.xml
@@ -43,6 +43,17 @@
             <version>${angus-activation.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.jodd</groupId>
+            <artifactId>jodd-util</artifactId>
+            <version>6.2.1</version>
+        </dependency>
+        <dependency>
+            <groupId>com.j256.simplemagic</groupId>
+            <artifactId>simplemagic</artifactId>
+            <version>1.17</version>
+        </dependency>
+
     </dependencies>
 
     <build>
diff --git a/core-java-modules/core-java-io/src/test/java/com/baeldung/extension/ExtensionFromMimeTypeUnitTest.java b/core-java-modules/core-java-io/src/test/java/com/baeldung/extension/ExtensionFromMimeTypeUnitTest.java
new file mode 100644
index 0000000000..f8f42861cc
--- /dev/null
+++ b/core-java-modules/core-java-io/src/test/java/com/baeldung/extension/ExtensionFromMimeTypeUnitTest.java
@@ -0,0 +1,62 @@
+package com.baeldung.extension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.tika.mime.MimeTypeException;
+
+import org.junit.Test;
+
+import com.j256.simplemagic.ContentInfo;
+
+public class ExtensionFromMimeTypeUnitTest {
+    private static final String IMAGE_JPEG_MIME_TYPE = "image/jpeg";
+    @Test
+    public void whenUsingTika_thenGetFileExtension() throws MimeTypeException {
+        List<String> expectedExtensions = Arrays.asList(".jpg", ".jpeg", ".jpe", ".jif", ".jfif", ".jfi");
+        org.apache.tika.mime.MimeTypes allTypes = org.apache.tika.mime.MimeTypes.getDefaultMimeTypes();
+        org.apache.tika.mime.MimeType type = allTypes.forName(IMAGE_JPEG_MIME_TYPE);
+        String primaryExtension = type.getExtension();
+        assertEquals(".jpg", primaryExtension);
+        List<String> detectedExtensions = type.getExtensions();
+        assertThat(detectedExtensions).containsExactlyElementsOf(expectedExtensions);
+    }
+
+    @Test
+    public void  whenUsingJodd_thenGetFileExtension() {
+        List<String> expectedExtensions = Arrays.asList("jpeg", "jpg", "jpe");
+        String[] detectedExtensions = jodd.net.MimeTypes.findExtensionsByMimeTypes(IMAGE_JPEG_MIME_TYPE, false);
+        assertThat(detectedExtensions).containsExactlyElementsOf(expectedExtensions);
+    }
+
+    @Test
+    public void whenUsingMimetypesFileTypeMap_thenGetFileExtension() {
+        List<String> expectedExtensions = Arrays.asList("jpeg", "jpg", "jpe");
+        ContentInfo contentInfo = new ContentInfo("", IMAGE_JPEG_MIME_TYPE, "", true);
+        String[] detectedExtensions = contentInfo.getFileExtensions();
+        assertThat(detectedExtensions).containsExactlyElementsOf(expectedExtensions);
+    }
+
+    @Test
+    public void whenUsingCustomLogic_thenGetFileExtension() {
+        Map<String, Set<String>> mimeExtensionsMap = new HashMap<>();
+        List<String> expectedExtensions = Arrays.asList(".jpg", ".jpe", ".jpeg");
+        addMimeExtensions(mimeExtensionsMap, "image/jpeg", ".jpg");
+        addMimeExtensions(mimeExtensionsMap, "image/jpeg", ".jpe");
+        addMimeExtensions(mimeExtensionsMap, "image/jpeg", ".jpeg");
+
+        Set<String> detectedExtensions = mimeExtensionsMap.get(IMAGE_JPEG_MIME_TYPE);
+        assertThat(detectedExtensions).containsExactlyElementsOf(expectedExtensions);
+    }
+
+    private void addMimeExtensions(Map<String, Set<String>> map, String mimeType, String extension) {
+        map.computeIfAbsent(mimeType, k -> new HashSet<>()).add(extension);
+    }
+}