diff --git a/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java b/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java
index b3af58a..22e8079 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java
@@ -36,6 +36,7 @@ import javax.servlet.http.HttpServletRequest;
 import net.sourceforge.plantuml.BlockUml;
 import net.sourceforge.plantuml.FileFormat;
 import net.sourceforge.plantuml.FileFormatOption;
+import net.sourceforge.plantuml.OptionFlags;
 import net.sourceforge.plantuml.NullOutputStream;
 import net.sourceforge.plantuml.SourceStringReader;
 import net.sourceforge.plantuml.StringUtils;
diff --git a/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java b/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
index 43fd8f7..eed3887 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
@@ -37,6 +37,7 @@ import javax.servlet.http.HttpServletResponse;
 
 import net.sourceforge.plantuml.BlockUml;
 import net.sourceforge.plantuml.FileFormat;
+import net.sourceforge.plantuml.OptionFlags;
 import net.sourceforge.plantuml.SourceStringReader;
 import net.sourceforge.plantuml.core.Diagram;
 import net.sourceforge.plantuml.core.UmlSource;
diff --git a/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java b/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java
index fd996c3..ffde3f2 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java
@@ -24,6 +24,7 @@
 package net.sourceforge.plantuml.servlet;
 
 import net.sourceforge.plantuml.FileFormat;
+import net.sourceforge.plantuml.OptionFlags;
 import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
 
 import javax.imageio.IIOException;
diff --git a/src/main/java/net/sourceforge/plantuml/servlet/utility/UmlExtractor.java b/src/main/java/net/sourceforge/plantuml/servlet/utility/UmlExtractor.java
index fd6b789..1aeca9b 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/utility/UmlExtractor.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/utility/UmlExtractor.java
@@ -27,6 +27,7 @@ import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 
+import net.sourceforge.plantuml.OptionFlags;
 import net.sourceforge.plantuml.code.Transcoder;
 import net.sourceforge.plantuml.code.TranscoderUtil;