8308184: Launching java with large number of jars in classpath with java.protocol.handler.pkgs system property set can lead to StackOverflowError

Reviewed-by: mchung, alanb

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

@@ -53,11 +53,9 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Properties;
-import java.util.Set;
 import java.util.StringTokenizer;
 import java.util.jar.JarFile;
 import java.util.zip.CRC32;
@@ -209,7 +207,9 @@ public class URLClassPath {
 
         this.unopenedUrls = unopenedUrls;
         this.path = path;
-        this.jarHandler = null;
+        // the application class loader uses the built-in protocol handler to avoid protocol
+        // handler lookup when opening JAR files on the class path.
+        this.jarHandler = new sun.net.www.protocol.jar.Handler();
         this.acc = null;
     }
 

test/jdk/sun/misc/URLClassPath/LargeClasspathWithPkgPrefix.java

@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2023, 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.
+ *
+ * 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.
+ */
+
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import jdk.test.lib.JDKToolFinder;
+import jdk.test.lib.compiler.CompilerUtils;
+import jdk.test.lib.process.OutputAnalyzer;
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.util.JarBuilder;
+
+/*
+ * @test
+ * @bug 8308184
+ * @summary Verify that an application can be launched when the classpath contains large number of
+ *          jars and the java.protocol.handler.pkgs system property is set
+ * @library /test/lib/
+ * @build jdk.test.lib.util.JarBuilder jdk.test.lib.compiler.CompilerUtils
+ *        jdk.test.lib.process.ProcessTools
+ * @run driver LargeClasspathWithPkgPrefix
+ */
+public class LargeClasspathWithPkgPrefix {
+
+    private static final Path CWD = Path.of(".");
+
+    private static final String JAVA_MAIN_CONTENT = """
+            public class Foo {
+                public static void main(String[] args) throws Exception {
+                    if (args.length != 0) {
+                        System.out.println("unexpected args: " + java.util.Arrays.toString(args));
+                        System.exit(1);
+                    }
+                    System.out.println("Running application on Java version: "
+                                + System.getProperty("java.version"));
+                    System.out.println("Application launched with java.protocol.handler.pkgs="
+                                + System.getProperty("java.protocol.handler.pkgs"));
+                    System.out.println("Application launched with classpath: "
+                                + System.getProperty("java.class.path"));
+                    System.out.println("Hello World");
+                }
+            }
+            """;
+
+    public static void main(final String[] args) throws Exception {
+        // dir to which the application main's .class file will be compiled to
+        Path classesDir = Files.createTempDirectory(CWD, "8308184-classes").toAbsolutePath();
+        // dir contains many jars
+        Path libDir = Files.createTempDirectory(CWD, "8308184-libs").toAbsolutePath();
+        Files.createDirectories(libDir);
+
+        // trivial jar file
+        Path jarPath = Path.of(libDir.toString(), "8308184-dummy.jar");
+        createJar(jarPath);
+
+        // create multiple such jar files in the lib dir
+        int numCopies = 750;
+        long start = System.currentTimeMillis();
+        for (int i = 1; i <= numCopies; i++) {
+            Path dest = Path.of(libDir.toString(), "8308184-dummy-" + i + ".jar");
+            Files.copy(jarPath, dest);
+        }
+        long end = System.currentTimeMillis();
+        System.out.println("Created " + numCopies + " jars under " + libDir
+                + ", took " + (end - start) + " milli seconds");
+
+        // create the application's main java file
+        Path fooJavaSrcFile = Path.of(classesDir.toString(), "Foo.java");
+        Files.writeString(fooJavaSrcFile, JAVA_MAIN_CONTENT);
+
+        // compile this java file
+        compile(fooJavaSrcFile, classesDir);
+
+        // Create the classpath string. It is important that the classes directory which contains
+        // application's main class, is at the end of the classpath (or too far into the classpath).
+        // The initial entries in the classpath should be jar files.
+        // constructed classpath is of the form -cp lib/*:classes/
+        // (the * in lib/* is parsed/interpreted by the java launcher and includes all jars in that
+        // directory)
+        String classpath = File.pathSeparator + libDir.toString() + "/*"
+                + File.pathSeparator + classesDir.toString();
+        // launch the application
+        launchApplication(classpath);
+        // test passed successfully, we don't need the lib directory which has too many jars,
+        // anymore. we let the dir stay only if the test fails, for debug purpose
+        libDir.toFile().deleteOnExit();
+    }
+
+    // creates a trivial jar file
+    private static void createJar(Path p) throws Exception {
+        JarBuilder jb = new JarBuilder(p.toString());
+        jb.addEntry("foobar.txt", "foobar".getBytes());
+        jb.build();
+        System.out.println("Created jar at " + p);
+    }
+
+    // compile <javaFile> to <destDir>
+    private static void compile(Path javaFile, Path destDir) throws Exception {
+        boolean compiled = CompilerUtils.compile(javaFile, destDir);
+        if (!compiled) {
+            // compilation failure log/reason would already be available on System.out/err
+            throw new AssertionError("Compilation failed for " + javaFile);
+        }
+    }
+
+    // java -Djava.protocol.handler.pkgs=foo.bar.some.nonexistent.pkg -cp <classpath> Foo
+    private static void launchApplication(String classPath) throws Exception {
+        String java = JDKToolFinder.getJDKTool("java");
+        ProcessBuilder pb = new ProcessBuilder(java,
+                "-Djava.protocol.handler.pkgs=foo.bar.some.nonexistent.pkg",
+                "-cp", classPath,
+                "Foo");
+        pb.directory(CWD.toFile());
+        System.out.println("Launching java application: " + pb.command());
+        OutputAnalyzer analyzer = ProcessTools.executeProcess(pb);
+        analyzer.shouldHaveExitValue(0);
+        analyzer.shouldContain("Hello World");
+    }
+}