--- old/src/hotspot/share/utilities/ostream.cpp	2020-04-10 20:11:12.265307061 +0800
+++ new/src/hotspot/share/utilities/ostream.cpp	2020-04-10 20:11:12.067312857 +0800
@@ -565,7 +565,9 @@
 }
 
 void fileStream::flush() {
-  fflush(_file);
+  if (_file != NULL) {
+    fflush(_file);
+  }
 }
 
 void fdStream::write(const char* s, size_t len) {