diff --git a/src/compiler/capnpc-java.c++ b/src/compiler/capnpc-java.c++
index 8366510..f467b14 100644
--- a/src/compiler/capnpc-java.c++
+++ b/src/compiler/capnpc-java.c++
@@ -190,7 +190,7 @@ private:
   std::unordered_set<uint64_t> usedImports;
   bool hasInterfaces = false;
 
-  kj::StringPtr outerClassName;
+  kj::String outerClassName;
 
   kj::StringTree javaFullName(Schema schema) {
     auto node = schema.getProto();