/*
 * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package jdk.internal.loader;

import java.io.IOException;
import java.io.InputStream;
import java.lang.module.ModuleReference;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.concurrent.ConcurrentHashMap;
import java.util.jar.JarInputStream;
import java.util.jar.Manifest;
import java.util.stream.Stream;

import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.module.Modules;
import jdk.internal.module.ServicesCatalog;
import jdk.internal.util.StaticProperty;

Find resources and packages in modules defined to the boot class loader or resources and packages on the "boot class path" specified via -Xbootclasspath/a.
/** * Find resources and packages in modules defined to the boot class loader or * resources and packages on the "boot class path" specified via -Xbootclasspath/a. */
public class BootLoader { private BootLoader() { } // The unnamed module for the boot loader private static final Module UNNAMED_MODULE; private static final String JAVA_HOME = StaticProperty.javaHome(); static { UNNAMED_MODULE = SharedSecrets.getJavaLangAccess().defineUnnamedModule(null); setBootLoaderUnnamedModule0(UNNAMED_MODULE); } // ServiceCatalog for the boot class loader private static final ServicesCatalog SERVICES_CATALOG; static { ArchivedClassLoaders archivedClassLoaders = ArchivedClassLoaders.get(); if (archivedClassLoaders != null) { SERVICES_CATALOG = archivedClassLoaders.servicesCatalog(null); } else { SERVICES_CATALOG = ServicesCatalog.create(); } } // ClassLoaderValue map for the boot class loader private static final ConcurrentHashMap<?, ?> CLASS_LOADER_VALUE_MAP = new ConcurrentHashMap<>(); // native libraries loaded by the boot class loader private static final NativeLibraries NATIVE_LIBS = NativeLibraries.jniNativeLibraries(null);
Returns the unnamed module for the boot loader.
/** * Returns the unnamed module for the boot loader. */
public static Module getUnnamedModule() { return UNNAMED_MODULE; }
Returns the ServiceCatalog for modules defined to the boot class loader.
/** * Returns the ServiceCatalog for modules defined to the boot class loader. */
public static ServicesCatalog getServicesCatalog() { return SERVICES_CATALOG; }
Returns the ClassLoaderValue map for the boot class loader.
/** * Returns the ClassLoaderValue map for the boot class loader. */
public static ConcurrentHashMap<?, ?> getClassLoaderValueMap() { return CLASS_LOADER_VALUE_MAP; }
Returns NativeLibraries for the boot class loader.
/** * Returns NativeLibraries for the boot class loader. */
public static NativeLibraries getNativeLibraries() { return NATIVE_LIBS; }
Returns true if there is a class path associated with the BootLoader.
/** * Returns {@code true} if there is a class path associated with the * BootLoader. */
public static boolean hasClassPath() { return ClassLoaders.bootLoader().hasClassPath(); }
Registers a module with this class loader so that its classes (and resources) become visible via this class loader.
/** * Registers a module with this class loader so that its classes * (and resources) become visible via this class loader. */
public static void loadModule(ModuleReference mref) { ClassLoaders.bootLoader().loadModule(mref); }
Loads the Class object with the given name defined to the boot loader.
/** * Loads the Class object with the given name defined to the boot loader. */
public static Class<?> loadClassOrNull(String name) { return ClassLoaders.bootLoader().loadClassOrNull(name); }
Loads the Class object with the given name in the given module defined to the boot loader. Returns null if not found.
/** * Loads the Class object with the given name in the given module * defined to the boot loader. Returns {@code null} if not found. */
public static Class<?> loadClass(Module module, String name) { Class<?> c = loadClassOrNull(name); if (c != null && c.getModule() == module) { return c; } else { return null; } }
Loads a native library from the system library path.
/** * Loads a native library from the system library path. */
public static void loadLibrary(String name) { if (System.getSecurityManager() == null) { BootLoader.getNativeLibraries().loadLibrary(name); } else { AccessController.doPrivileged(new java.security.PrivilegedAction<>() { public Void run() { BootLoader.getNativeLibraries().loadLibrary(name); return null; } }); } }
Returns a URL to a resource in a module defined to the boot loader.
/** * Returns a URL to a resource in a module defined to the boot loader. */
public static URL findResource(String mn, String name) throws IOException { return ClassLoaders.bootLoader().findResource(mn, name); }
Returns an input stream to a resource in a module defined to the boot loader.
/** * Returns an input stream to a resource in a module defined to the * boot loader. */
public static InputStream findResourceAsStream(String mn, String name) throws IOException { return ClassLoaders.bootLoader().findResourceAsStream(mn, name); }
Returns the URL to the given resource in any of the modules defined to the boot loader and the boot class path.
/** * Returns the URL to the given resource in any of the modules * defined to the boot loader and the boot class path. */
public static URL findResource(String name) { return ClassLoaders.bootLoader().findResource(name); }
Returns an Iterator to iterate over the resources of the given name in any of the modules defined to the boot loader.
/** * Returns an Iterator to iterate over the resources of the given name * in any of the modules defined to the boot loader. */
public static Enumeration<URL> findResources(String name) throws IOException { return ClassLoaders.bootLoader().findResources(name); }
Define a package for the given class to the boot loader, if not already defined.
/** * Define a package for the given class to the boot loader, if not already * defined. */
public static Package definePackage(Class<?> c) { return getDefinedPackage(c.getPackageName()); }
Returns the Package of the given name defined to the boot loader or null if the package has not been defined.
/** * Returns the Package of the given name defined to the boot loader or null * if the package has not been defined. */
public static Package getDefinedPackage(String pn) { Package pkg = ClassLoaders.bootLoader().getDefinedPackage(pn); if (pkg == null) { String location = getSystemPackageLocation(pn.replace('.', '/')); if (location != null) { pkg = PackageHelper.definePackage(pn.intern(), location); } } return pkg; }
Returns a stream of the packages defined to the boot loader.
/** * Returns a stream of the packages defined to the boot loader. */
public static Stream<Package> packages() { return Arrays.stream(getSystemPackageNames()) .map(name -> getDefinedPackage(name.replace('/', '.'))); }
Helper class to define Package objects for packages in modules defined to the boot loader.
/** * Helper class to define {@code Package} objects for packages in modules * defined to the boot loader. */
static class PackageHelper { private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
Define the Package with the given name. The specified location is a jrt URL to a named module in the run-time image, a file URL to a module in an exploded run-time image, or a file path to an entry on the boot class path (java agent Boot-Class-Path or -Xbootclasspath/a.

If the given location is a JAR file containing a manifest, the defined Package contains the versioning information from the manifest, if present.

Params:
  • name – package name
  • location – location where the package is (jrt URL or file URL for a named module in the run-time or exploded image; a file path for a package from -Xbootclasspath/a)
/** * Define the {@code Package} with the given name. The specified * location is a jrt URL to a named module in the run-time image, * a file URL to a module in an exploded run-time image, or a file * path to an entry on the boot class path (java agent Boot-Class-Path * or -Xbootclasspath/a. * * <p> If the given location is a JAR file containing a manifest, * the defined Package contains the versioning information from * the manifest, if present. * * @param name package name * @param location location where the package is (jrt URL or file URL * for a named module in the run-time or exploded image; * a file path for a package from -Xbootclasspath/a) */
static Package definePackage(String name, String location) { Module module = findModule(location); if (module != null) { // named module from runtime image or exploded module if (name.isEmpty()) throw new InternalError("empty package in " + location); return JLA.definePackage(ClassLoaders.bootLoader(), name, module); } // package in unnamed module (-Xbootclasspath/a) URL url = toFileURL(location); Manifest man = url != null ? getManifest(location) : null; return ClassLoaders.bootLoader().defineOrCheckPackage(name, man, url); }
Finds the module at the given location defined to the boot loader. The module is either in runtime image or exploded image. Otherwise this method returns null.
/** * Finds the module at the given location defined to the boot loader. * The module is either in runtime image or exploded image. * Otherwise this method returns null. */
private static Module findModule(String location) { String mn = null; if (location.startsWith("jrt:/")) { // named module in runtime image ("jrt:/".length() == 5) mn = location.substring(5, location.length()); } else if (location.startsWith("file:/")) { // named module in exploded image Path path = Path.of(URI.create(location)); Path modulesDir = Path.of(JAVA_HOME, "modules"); if (path.startsWith(modulesDir)) { mn = path.getFileName().toString(); } } // return the Module object for the module name. The Module may // in the boot layer or a child layer for the case that the module // is loaded into a running VM if (mn != null) { String name = mn; return Modules.findLoadedModule(mn) .orElseThrow(() -> new InternalError(name + " not loaded")); } else { return null; } }
Returns URL if the given location is a regular file path.
/** * Returns URL if the given location is a regular file path. */
private static URL toFileURL(String location) { return AccessController.doPrivileged(new PrivilegedAction<>() { public URL run() { Path path = Path.of(location); if (Files.isRegularFile(path)) { try { return path.toUri().toURL(); } catch (MalformedURLException e) {} } return null; } }); }
Returns the Manifest if the given location is a JAR file containing a manifest.
/** * Returns the Manifest if the given location is a JAR file * containing a manifest. */
private static Manifest getManifest(String location) { return AccessController.doPrivileged(new PrivilegedAction<>() { public Manifest run() { Path jar = Path.of(location); try (InputStream in = Files.newInputStream(jar); JarInputStream jis = new JarInputStream(in, false)) { return jis.getManifest(); } catch (IOException e) { return null; } } }); } }
Returns an array of the binary name of the packages defined by the boot loader, in VM internal form (forward slashes instead of dot).
/** * Returns an array of the binary name of the packages defined by * the boot loader, in VM internal form (forward slashes instead of dot). */
private static native String[] getSystemPackageNames();
Returns the location of the package of the given name, if defined by the boot loader; otherwise null is returned. The location may be a module from the runtime image or exploded image, or from the boot class append path (i.e. -Xbootclasspath/a or BOOT-CLASS-PATH attribute specified in java agent).
/** * Returns the location of the package of the given name, if * defined by the boot loader; otherwise {@code null} is returned. * * The location may be a module from the runtime image or exploded image, * or from the boot class append path (i.e. -Xbootclasspath/a or * BOOT-CLASS-PATH attribute specified in java agent). */
private static native String getSystemPackageLocation(String name); private static native void setBootLoaderUnnamedModule0(Module module); }