--- old/test/lib/testlibrary/ClassFileInstaller.java	2019-08-13 21:56:38.609547653 +0000
+++ new/test/lib/testlibrary/ClassFileInstaller.java	2019-08-13 21:56:38.509547486 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2018, 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
@@ -21,36 +21,237 @@
  * questions.
  */
 
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.FileNotFoundException;
 import java.io.InputStream;
+import java.io.ByteArrayInputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
 
 /**
- * Dump a class file for a class on the class path in the current directory
+ * Dump a class file for a class on the class path in the current directory, or
+ * in the specified JAR file. This class is usually used when you build a class
+ * from a test library, but want to use this class in a sub-process.
+ *
+ * For example, to build the following library class:
+ * test/lib/sun/hotspot/WhiteBox.java
+ *
+ * You would use the following tags:
+ *
+ * @library /test/lib
+ * @build sun.hotspot.WhiteBox
+ *
+ * JTREG would build the class file under
+ * ${JTWork}/classes/test/lib/sun/hotspot/WhiteBox.class
+ *
+ * With you run your main test class using "@run main MyMainClass", JTREG would setup the
+ * -classpath to include "${JTWork}/classes/test/lib/", so MyMainClass would be able to
+ * load the WhiteBox class.
+ *
+ * However, if you run a sub process, and do not wish to use the exact same -classpath,
+ * You can use ClassFileInstaller to ensure that WhiteBox is available in the current
+ * directory of your test:
+ *
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ *
+ * Or, you can use the -jar option to store the class in the specified JAR file. If a relative
+ * path name is given, the JAR file would be relative to the current directory of
+ *
+ * @run main ClassFileInstaller -jar myjar.jar sun.hotspot.WhiteBox
  */
 public class ClassFileInstaller {
     /**
+     * You can enable debug tracing of ClassFileInstaller by running JTREG with
+     * jtreg -DClassFileInstaller.debug=true ... <names of tests>
+     */
+    public static boolean DEBUG = Boolean.getBoolean("ClassFileInstaller.debug");
+
+    /**
      * @param args The names of the classes to dump
      * @throws Exception
      */
     public static void main(String... args) throws Exception {
-        for (String arg : args) {
-            ClassLoader cl = ClassFileInstaller.class.getClassLoader();
+        if (args.length > 1 && args[0].equals("-jar")) {
+            if (args.length < 2) {
+                throw new RuntimeException("Usage: ClassFileInstaller <options> <classes>\n" +
+                                           "where possible options include:\n" +
+                                           "  -jar <path>             Write to the JAR file <path>");
+            }
+            writeJar(args[1], null, args, 2, args.length);
+        } else {
+            if (DEBUG) {
+                System.out.println("ClassFileInstaller: Writing to " + System.getProperty("user.dir"));
+            }
+            for (String arg : args) {
+                writeClassToDisk(arg);
+            }
+        }
+    }
+
+    public static class Manifest {
+        private InputStream in;
+
+        private Manifest(InputStream in) {
+            this.in = in;
+        }
+
+        static Manifest fromSourceFile(String fileName) throws Exception {
+            String pathName = System.getProperty("test.src") + File.separator + fileName;
+            return new Manifest(new FileInputStream(pathName));
+        }
+
+        // Example:
+        //  String manifest = "Premain-Class: RedefineClassHelper\n" +
+        //                "Can-Redefine-Classes: true\n";
+        //  ClassFileInstaller.writeJar("redefineagent.jar",
+        //    ClassFileInstaller.Manifest.fromString(manifest),
+        //    "RedefineClassHelper");
+        static Manifest fromString(String manifest) throws Exception {
+            return new Manifest(new ByteArrayInputStream(manifest.getBytes()));
+        }
+
+        public InputStream getInputStream() {
+            return in;
+        }
+    }
+
+    private static void writeJar(String jarFile, Manifest manifest, String classes[], int from, int to) throws Exception {
+        if (DEBUG) {
+            System.out.println("ClassFileInstaller: Writing to " + getJarPath(jarFile));
+        }
+
+        (new File(jarFile)).delete();
+        FileOutputStream fos = new FileOutputStream(jarFile);
+        ZipOutputStream zos = new ZipOutputStream(fos);
+
+        // The manifest must be the first or second entry. See comments in JarInputStream
+        // constructor and JDK-5046178.
+        if (manifest != null) {
+            writeToDisk(zos, "META-INF/MANIFEST.MF", manifest.getInputStream());
+        }
+
+        for (int i=from; i<to; i++) {
+            writeClassToDisk(zos, classes[i]);
+        }
+
+        zos.close();
+        fos.close();
+    }
+
+    /*
+     * You can call ClassFileInstaller.writeJar() from your main test class instead of
+     * using "@run ClassFileInstaller -jar ...". E.g.,
+     *
+     * String jarPath = ClassFileInstaller.getJarPath("myjar.jar", "sun.hotspot.WhiteBox")
+     *
+     * If you call this API, make sure you build ClassFileInstaller with the following tags:
+     *
+     * @library testlibrary
+     * @build ClassFileInstaller
+     */
+    public static String writeJar(String jarFile, String... classes) throws Exception {
+        writeJar(jarFile, null, classes, 0, classes.length);
+        return getJarPath(jarFile);
+    }
 
-            // Convert dotted class name to a path to a class file
-            String pathName = arg.replace('.', '/').concat(".class");
-            InputStream is = cl.getResourceAsStream(pathName);
+    public static String writeJar(String jarFile, Manifest manifest, String... classes) throws Exception {
+        writeJar(jarFile, manifest, classes, 0, classes.length);
+        return getJarPath(jarFile);
+    }
+
+    /**
+     * This returns the absolute path to the file specified in "@ClassFileInstaller -jar myjar.jar",
+     * In your test program, instead of using the JAR file name directly:
+     *
+     * String jarPath = "myjar.jar";
+     *
+     * you should call this function, like:
+     *
+     * String jarPath = ClassFileInstaller.getJarPath("myjar.jar")
+     *
+     * The reasons are:
+     * (1) Using absolute path makes it easy to cut-and-paste from the JTR file and rerun your
+     *     test in any directory.
+     * (2) In the future, we may make the JAR file name unique to avoid clobbering
+     *     during parallel JTREG execution.
+     *
+     */
+    public static String getJarPath(String jarFileName) {
+        return new File(jarFileName).getAbsolutePath();
+    }
+
+    public static void writeClassToDisk(String className) throws Exception {
+        writeClassToDisk((ZipOutputStream)null, className);
+    }
+    private static void writeClassToDisk(ZipOutputStream zos, String className) throws Exception {
+        writeClassToDisk(zos, className, "");
+    }
 
+    public static void writeClassToDisk(String className, String prependPath) throws Exception {
+        writeClassToDisk(null, className, prependPath);
+    }
+    private static void writeClassToDisk(ZipOutputStream zos, String className, String prependPath) throws Exception {
+        ClassLoader cl = ClassFileInstaller.class.getClassLoader();
+
+        // Convert dotted class name to a path to a class file
+        String pathName = className.replace('.', '/').concat(".class");
+        InputStream is = cl.getResourceAsStream(pathName);
+        if (is == null) {
+            throw new RuntimeException("Failed to find " + pathName);
+        }
+        if (prependPath.length() > 0) {
+            pathName = prependPath + "/" + pathName;
+        }
+        writeToDisk(zos, pathName, is);
+    }
+
+    public static void writeClassToDisk(String className, byte[] bytecode) throws Exception {
+        writeClassToDisk(null, className, bytecode);
+    }
+    private static void writeClassToDisk(ZipOutputStream zos, String className, byte[] bytecode) throws Exception {
+        writeClassToDisk(zos, className, bytecode, "");
+    }
+
+    public static void writeClassToDisk(String className, byte[] bytecode, String prependPath) throws Exception {
+        writeClassToDisk(null, className, bytecode, prependPath);
+    }
+    private static void writeClassToDisk(ZipOutputStream zos, String className, byte[] bytecode, String prependPath) throws Exception {
+        // Convert dotted class name to a path to a class file
+        String pathName = className.replace('.', '/').concat(".class");
+        if (prependPath.length() > 0) {
+            pathName = prependPath + "/" + pathName;
+        }
+        writeToDisk(zos, pathName, new ByteArrayInputStream(bytecode));
+    }
+
+    private static void writeToDisk(ZipOutputStream zos, String pathName, InputStream is) throws Exception {
+        if (DEBUG) {
+            System.out.println("ClassFileInstaller: Writing " + pathName);
+        }
+        if (zos != null) {
+            ZipEntry ze = new ZipEntry(pathName);
+            zos.putNextEntry(ze);
+            byte[] buf = new byte[1024];
+            int len;
+            while ((len = is.read(buf))>0){
+                zos.write(buf, 0, len);
+            }
+        } else {
             // Create the class file's package directory
             Path p = Paths.get(pathName);
-            Path parent = p.getParent();
-            if (parent != null) {
-                Files.createDirectories(parent);
+            if (pathName.contains("/")) {
+                Files.createDirectories(p.getParent());
             }
             // Create the class file
             Files.copy(is, p, StandardCopyOption.REPLACE_EXISTING);
         }
+        is.close();
     }
 }