2 files changed, 12 insertions, 2 deletions
diff --git a/src/main/java/org/zwobble/mammoth/internal/docx/ContentTypes.java b/src/main/java/org/zwobble/mammoth/internal/docx/ContentTypes.java
index e778f73..b2677b2 100644
--- a/src/main/java/org/zwobble/mammoth/internal/docx/ContentTypes.java
+++ b/src/main/java/org/zwobble/mammoth/internal/docx/ContentTypes.java
@@ -1,7 +1,7 @@
 package org.zwobble.mammoth.internal.docx;
 
-import com.google.common.io.Files;
 import org.zwobble.mammoth.internal.util.MammothMaps;
+import org.zwobble.mammoth.internal.util.Paths;
 
 import java.util.Map;
 import java.util.Optional;
@@ -34,7 +34,7 @@ public class ContentTypes {
         if (overrides.containsKey(path)) {
             return lookup(overrides, path);
         } else {
-            String extension = Files.getFileExtension(path);
+            String extension = Paths.getExtension(path);
             if (extensionDefaults.containsKey(extension)) {
                 return lookup(extensionDefaults, extension);
             } else {
diff --git a/src/main/java/org/zwobble/mammoth/internal/util/Paths.java b/src/main/java/org/zwobble/mammoth/internal/util/Paths.java
new file mode 100644
index 0000000..7448905
--- /dev/null
+++ b/src/main/java/org/zwobble/mammoth/internal/util/Paths.java
@@ -0,0 +1,10 @@
+package org.zwobble.mammoth.internal.util;
+
+public class Paths {
+    private Paths() {}
+
+    public static String getExtension(String path) {
+        int dotIndex = path.lastIndexOf('.');
+        return dotIndex == -1 ? "" : path.substring(dotIndex + 1);
+    }
+}