--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/VanillaJavaBuilder.java.ORIG	1980-01-01 00:00:00.000000000 +0100
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/VanillaJavaBuilder.java	2022-02-14 12:35:42.699774117 +0100
@@ -78,7 +78,9 @@
   private FileSystem getJarFileSystem(Path sourceJar) throws IOException {
     FileSystem fs = filesystems.get(sourceJar);
     if (fs == null) {
-      filesystems.put(sourceJar, fs = FileSystems.newFileSystem(sourceJar, null));
+      // used for disambiguation from newFileSystem(Path path, Map<String,?> env)
+      java.lang.ClassLoader nullClassLoader = null;
+      filesystems.put(sourceJar, fs = FileSystems.newFileSystem(sourceJar, nullClassLoader));
     }
     return fs;
   }