src/java.base/share/classes/jdk/internal/loader/BuiltinClassLoader.java

@@ -102,12 +102,11 @@
 
     // parent ClassLoader
     private final BuiltinClassLoader parent;
 
     // the URL class path, or null if there is no class path
-    private final URLClassPath ucp;
-
+    private @Stable URLClassPath ucp;
 
     /**
      * A module defined/loaded by a built-in class loader.
      *
      * A LoadedModule encapsulates a ModuleReference along with its CodeSource

@@ -154,14 +153,30 @@
             }
             return url;
         }
     }
 
-
     // maps package name to loaded module for modules in the boot layer
-    private static final Map<String, LoadedModule> packageToModule
-        = new ConcurrentHashMap<>(1024);
+    private static final Map<String, LoadedModule> packageToModule;
+    static {
+        ArchivedClassLoaders archivedClassLoaders = ArchivedClassLoaders.get();
+        if (archivedClassLoaders != null) {
+            @SuppressWarnings("unchecked")
+            Map<String, LoadedModule> map
+                = (Map<String, LoadedModule>) archivedClassLoaders.packageToModule();
+            packageToModule = map;
+        } else {
+            packageToModule = new ConcurrentHashMap<>(1024);
+        }
+    }
+
+    /**
+     * Invoked by ArchivedClassLoaders to archive the package-to-module map.
+     */
+    static Map<String, ?> packageToModule() {
+        return packageToModule;
+    }
 
     // maps a module name to a module reference
     private final Map<String, ModuleReference> nameToModule;
 
     // maps a module reference to a module reader

@@ -184,10 +199,25 @@
         this.nameToModule = new ConcurrentHashMap<>(32);
         this.moduleToReader = new ConcurrentHashMap<>();
     }
 
     /**
+     * Appends to the given file path to the class path.
+     */
+    void appendClassPath(String path) {
+        // assert ucp != null;
+        ucp.addFile(path);
+    }
+
+    /**
+     * Sets the class path, called to reset the class path during -Xshare:dump
+     */
+    void setClassPath(URLClassPath ucp) {
+        this.ucp = ucp;
+    }
+
+    /**
      * Returns {@code true} if there is a class path associated with this
      * class loader.
      */
     boolean hasClassPath() {
         return ucp != null;

@@ -1040,6 +1070,11 @@
      * checking with java.net.URLClassLoader.
      */
     private static URL checkURL(URL url) {
         return URLClassPath.checkURL(url);
     }
+
+    // Called from VM only, during -Xshare:dump
+    private void resetArchivedStates() {
+        ucp = null;
+    }
 }