Add null check to UI.setTheme. (#15326)

Change-Id: I2ab2d24ec05bb618969f59ea15d3a971f88009ca

1 files changed, 6 insertions, 6 deletions

diff --git a/server/src/com/vaadin/ui/UI.java b/server/src/com/vaadin/ui/UI.java
index 44948dfb6f..4bd4b67259 100644
--- a/server/src/com/vaadin/ui/UI.java
+++ b/server/src/com/vaadin/ui/UI.java
@@ -633,11 +633,7 @@ public abstract class UI extends AbstractSingleComponentContainer implements
         this.embedId = embedId;
 
         // Actual theme - used for finding CustomLayout templates
-        String unescapedThemeName = request.getParameter("theme");
-        if (unescapedThemeName != null) {
-            // Set theme escapes the name
-            setTheme(unescapedThemeName);
-        }
+        setTheme(request.getParameter("theme"));
 
         getPage().init(request);
 
@@ -1168,7 +1164,11 @@ public abstract class UI extends AbstractSingleComponentContainer implements
      *            The new theme name
      */
     public void setTheme(String theme) {
-        getState().theme = VaadinServlet.stripSpecialChars(theme);
+        if(theme == null) {
+            getState().theme = null;
+        } else {
+            getState().theme = VaadinServlet.stripSpecialChars(theme);
+        }
     }
 
     /**