diff --git a/content/base/src/nsObjectLoadingContent.cpp b/content/base/src/nsObjectLoadingContent.cpp
index ebc52118ef5f..b129e7b80ac9 100644
--- a/content/base/src/nsObjectLoadingContent.cpp
+++ b/content/base/src/nsObjectLoadingContent.cpp
@@ -1459,12 +1459,15 @@ nsObjectLoadingContent::UpdateObjectParameters(bool aJavaURI)
   }
 
   if (isJava && hasCodebase && codebaseStr.IsEmpty()) {
-    // Java treats an empty codebase as the document codebase, but codebase=""
-    // as "/"
+    // Java treats codebase="" as "/"
     codebaseStr.AssignLiteral("/");
     // XXX(johns): This doesn't cover the case of "https:" which java would
     //             interpret as "https:///" but we interpret as this document's
     //             URI but with a changed scheme.
+  } else if (isJava && !hasCodebase) {
+    // Java expects a directory as the codebase, or else it will construct
+    // relative URIs incorrectly :(
+    codebaseStr.AssignLiteral(".");
   }
 
   if (!codebaseStr.IsEmpty()) {