From 27102380b3caa867e195a2ec84c70aeac860d782 Mon Sep 17 00:00:00 2001
From: Georgios Andrianakis <geoand@gmail.com>
Date: Fri, 12 Apr 2024 10:07:27 +0300
Subject: [PATCH] Improve loading of classes in RunnerClassLoader

This ClassLoader is already parallel capable, so just mark it as such.
Furthermore, we define the package without using the ClassLoader lock
by utilizing getDefinedPackage and checking for duplicate definitions

Co-authored-by: David M. Lloyd <david.lloyd@redhat.com>
---
 .../bootstrap/runner/RunnerClassLoader.java   | 77 ++++++++++++-------
 1 file changed, 48 insertions(+), 29 deletions(-)

diff --git a/independent-projects/bootstrap/runner/src/main/java/io/quarkus/bootstrap/runner/RunnerClassLoader.java b/independent-projects/bootstrap/runner/src/main/java/io/quarkus/bootstrap/runner/RunnerClassLoader.java
index 3e528969e5899..62c02e8fe08d3 100644
--- a/independent-projects/bootstrap/runner/src/main/java/io/quarkus/bootstrap/runner/RunnerClassLoader.java
+++ b/independent-projects/bootstrap/runner/src/main/java/io/quarkus/bootstrap/runner/RunnerClassLoader.java
@@ -26,6 +26,10 @@
  */
 public final class RunnerClassLoader extends ClassLoader {
 
+    static {
+        registerAsParallelCapable();
+    }
+
     /**
      * A map of resources by dir name. Root dir/default package is represented by the empty string
      */
@@ -101,18 +105,55 @@ public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundExce
                     continue;
                 }
                 definePackage(packageName, resources);
-                try {
-                    return defineClass(name, data, 0, data.length, resource.getProtectionDomain());
-                } catch (LinkageError e) {
-                    loaded = findLoadedClass(name);
-                    if (loaded != null) {
-                        return loaded;
+                return defineClass(name, data, resource);
+            }
+        }
+        return getParent().loadClass(name);
+    }
+
+    private void definePackage(String pkgName, ClassLoadingResource[] resources) {
+        if ((pkgName != null) && getDefinedPackage(pkgName) == null) {
+            for (ClassLoadingResource classPathElement : resources) {
+                ManifestInfo mf = classPathElement.getManifestInfo();
+                if (mf != null) {
+                    try {
+                        definePackage(pkgName, mf.getSpecTitle(),
+                                mf.getSpecVersion(),
+                                mf.getSpecVendor(),
+                                mf.getImplTitle(),
+                                mf.getImplVersion(),
+                                mf.getImplVendor(), null);
+                    } catch (IllegalArgumentException e) {
+                        var loaded = getDefinedPackage(pkgName);
+                        if (loaded == null) {
+                            throw e;
+                        }
                     }
+                    return;
+                }
+            }
+            try {
+                definePackage(pkgName, null, null, null, null, null, null, null);
+            } catch (IllegalArgumentException e) {
+                var loaded = getDefinedPackage(pkgName);
+                if (loaded == null) {
                     throw e;
                 }
             }
         }
-        return getParent().loadClass(name);
+    }
+
+    private Class<?> defineClass(String name, byte[] data, ClassLoadingResource resource) {
+        Class<?> loaded;
+        try {
+            return defineClass(name, data, 0, data.length, resource.getProtectionDomain());
+        } catch (LinkageError e) {
+            loaded = findLoadedClass(name);
+            if (loaded != null) {
+                return loaded;
+            }
+            throw e;
+        }
     }
 
     private void accessingResource(final ClassLoadingResource resource) {
@@ -219,28 +260,6 @@ protected Enumeration<URL> findResources(String name) {
         return Collections.enumeration(urls);
     }
 
-    private void definePackage(String pkgName, ClassLoadingResource[] resources) {
-        if ((pkgName != null) && getPackage(pkgName) == null) {
-            synchronized (getClassLoadingLock(pkgName)) {
-                if (getPackage(pkgName) == null) {
-                    for (ClassLoadingResource classPathElement : resources) {
-                        ManifestInfo mf = classPathElement.getManifestInfo();
-                        if (mf != null) {
-                            definePackage(pkgName, mf.getSpecTitle(),
-                                    mf.getSpecVersion(),
-                                    mf.getSpecVendor(),
-                                    mf.getImplTitle(),
-                                    mf.getImplVersion(),
-                                    mf.getImplVendor(), null);
-                            return;
-                        }
-                    }
-                    definePackage(pkgName, null, null, null, null, null, null, null);
-                }
-            }
-        }
-    }
-
     private String getPackageNameFromClassName(String className) {
         final int index = className.lastIndexOf('.');
         if (index == -1) {