src/jdk.jextract/share/classes/com/sun/tools/jextract/TypeDictionary.java

*** 64,73 ****
--- 64,76 ----
  
      private String recordOwnerClass(Type t) {
          try {
              //try resolve globally
              Path p = t.getDeclarationCursor().getSourceLocation().getFileLocation().path();
+             if (p == null) {
+                 p = Context.getBuiltinHeaderFile();
+             }
              HeaderFile hf = resolver.headerFor(p);
              return Utils.toInternalName(hf.pkgName, hf.headerClsName);
          } catch (Throwable ex) {
              //fallback: resolve locally. This can happen for two reasons: (i) the symbol to be resolved is a builtin
              //symbol (e.g. no header file has its definition), or (ii) when the declaration cursor points to an header file