src/jdk.jpackage/share/classes/jdk/jpackage/internal/AbstractAppImageBuilder.java

@@ -69,11 +69,11 @@
     public abstract void prepareJreFiles(
             Map<String, ? super Object> params) throws IOException;
     public abstract Path getAppDir();
     public abstract Path getAppModsDir();
 
-    public Path getRoot() {
+    public Path getRuntimeRoot() {
         return this.root;
     }
 
     protected void copyEntry(Path appDir, File srcdir, String fname)
             throws IOException {

@@ -173,10 +173,11 @@
         }
     }
 
     public void writeCfgFile(Map<String, ? super Object> params,
             File cfgFileName) throws IOException {
+        cfgFileName.getParentFile().mkdirs();
         cfgFileName.delete();
         File mainJar = JLinkBundlerHelper.getMainJar(params);
         ModFile.ModType mainJarType = ModFile.ModType.Unknown;
 
         if (mainJar != null) {

@@ -245,16 +246,16 @@
 
     File getRuntimeImageDir(File runtimeImageTop) {
         return runtimeImageTop;
     }
 
-    String getCfgAppDir() {
+    protected String getCfgAppDir() {
         return "$APPDIR" + File.separator
                 + getAppDir().getFileName() + File.separator;
     }
 
-    String getCfgRuntimeDir() {
+    protected String getCfgRuntimeDir() {
         return "$APPDIR" + File.separator + "runtime";
     }
 
     String getCfgClassPath(String classpath) {
         String cfgAppDir = getCfgAppDir();