[MODULES-439] Add a LoggerFinder implementation to load a finder base…

src/main/java/module-info.java

@@ -36,4 +36,5 @@
   uses java.lang.SecurityManager;
   uses java.security.Provider;
   uses org.jboss.modules.PreMain;
+  uses System.LoggerFinder;
 }

src/main/java/org/jboss/modules/Main.java

@@ -438,6 +438,9 @@ public static void main(String[] args) throws Throwable {
             }
         }
 
+        // Configure the ModuleLoggerFinder's class loader
+        ModuleLoggerFinder.setClassLoader(bootClassLoader);
+
         final String logManagerName = getServiceName(bootClassLoader, "java.util.logging.LogManager");
         if (logManagerName != null) {
             System.setProperty("java.util.logging.manager", logManagerName);

src/main/java/org/jboss/modules/ModuleLoggerFinder.java

@@ -0,0 +1,130 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ *
+ * Copyright 2023 Red Hat, Inc., and individual contributors
+ * as indicated by the @author tags.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jboss.modules;
+
+import java.lang.System.LoggerFinder;
+import java.util.EnumMap;
+import java.util.Map;
+import java.util.ResourceBundle;
+import java.util.ServiceLoader;
+import java.util.function.Supplier;
+import java.util.logging.Logger;
+
+/**
+ * A logger finder which attempts to locate a {@link LoggerFinder} on the
+ * {@linkplain java.util.logging.LogManager log managers} class path. If not found a default finder will be used.
+ *
+ * @author <a href="mailto:jperkins@redhat.com">James R. Perkins</a>
+ */
+public final class ModuleLoggerFinder extends LoggerFinder {
+
+    private final Supplier<LoggerFinder> defaultFinder = () -> new LoggerFinder() {
+        @Override
+        public System.Logger getLogger(final String name, final java.lang.Module module) {
+            return new JulSystemLogger(Logger.getLogger(name));
+        }
+    };
+    private static volatile ClassLoader classLoader;
+    private volatile LoggerFinder finder;
+
+    public ModuleLoggerFinder() {
+    }
+
+
+    @Override
+    public System.Logger getLogger(final String name, final java.lang.Module module) {
+        return resolveFinder().getLogger(name, module);
+    }
+
+    /**
+     * Sets the class loader to use when attempting to find the {@link LoggerFinder}.
+     *
+     * @param cl the class loader to use
+     */
+    static void setClassLoader(final ClassLoader cl) {
+        classLoader = cl;
+    }
+
+    private LoggerFinder resolveFinder() {
+        LoggerFinder result = finder;
+        if (result == null) {
+            synchronized (this) {
+                result = finder;
+                if (result == null) {
+                    try {
+                        final ClassLoader cl = classLoader;
+                        final ServiceLoader<LoggerFinder> loader = ServiceLoader.load(LoggerFinder.class, cl == null ? ClassLoader.getSystemClassLoader() : cl);
+                        for (LoggerFinder lf : loader) {
+                            if (!getClass().equals(lf.getClass())) {
+                                finder = result = lf;
+                                break;
+                            }
+                        }
+                        if (result == null) {
+                            finder = result = defaultFinder.get();
+                        }
+                    } catch (Throwable ignore) {
+                        finder = result = defaultFinder.get();
+                    }
+                }
+            }
+        }
+        return result;
+    }
+
+    private static class JulSystemLogger implements System.Logger {
+        private static final Map<System.Logger.Level, java.util.logging.Level> LEVELS = new EnumMap<>(System.Logger.Level.class);
+        private final java.util.logging.Logger delegate;
+
+        static {
+            LEVELS.put(System.Logger.Level.ALL, java.util.logging.Level.ALL);
+            LEVELS.put(System.Logger.Level.TRACE, java.util.logging.Level.FINER);
+            LEVELS.put(System.Logger.Level.DEBUG, java.util.logging.Level.FINE);
+            LEVELS.put(System.Logger.Level.INFO, java.util.logging.Level.INFO);
+            LEVELS.put(System.Logger.Level.WARNING, java.util.logging.Level.WARNING);
+            LEVELS.put(System.Logger.Level.ERROR, java.util.logging.Level.SEVERE);
+            LEVELS.put(System.Logger.Level.OFF, java.util.logging.Level.OFF);
+        }
+
+        private JulSystemLogger(final java.util.logging.Logger delegate) {
+            this.delegate = delegate;
+        }
+
+        @Override
+        public String getName() {
+            return delegate.getName();
+        }
+
+        @Override
+        public boolean isLoggable(final System.Logger.Level level) {
+            return delegate.isLoggable(LEVELS.getOrDefault(level, java.util.logging.Level.INFO));
+        }
+
+        @Override
+        public void log(final System.Logger.Level level, final ResourceBundle bundle, final String msg, final Throwable thrown) {
+            delegate.logrb(LEVELS.getOrDefault(level, java.util.logging.Level.INFO), bundle, msg, thrown);
+        }
+
+        @Override
+        public void log(final System.Logger.Level level, final ResourceBundle bundle, final String format, final Object... params) {
+            delegate.logrb(LEVELS.getOrDefault(level, java.util.logging.Level.INFO), bundle, format, params);
+        }
+    }
+}

src/main/resources/META-INF/services/java.lang.System$LoggerFinder

@@ -0,0 +1,20 @@
+#
+# JBoss, Home of Professional Open Source.
+#
+# Copyright 2018 Red Hat, Inc., and individual contributors
+# as indicated by the @author tags.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+org.jboss.modules.ModuleLoggerFinder