StatusLogger: Write to stderr by default

log4j-api-test/src/test/java/org/apache/logging/log4j/status/StatusLoggerTest.java

@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you 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.apache.logging.log4j.status;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class StatusLoggerTest {
+    private final PrintStream origOut = System.out;
+    private final PrintStream origErr = System.err;
+    private ByteArrayOutputStream outBuf;
+    private ByteArrayOutputStream errBuf;
+
+    @BeforeEach
+    void setupStreams() {
+        outBuf = new ByteArrayOutputStream();
+        errBuf = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outBuf));
+        System.setErr(new PrintStream(errBuf));
+    }
+
+    @AfterEach
+    void resetStreams() {
+        System.setOut(origOut);
+        System.setErr(origErr);
+    }
+
+    @Test
+    void status_logger_writes_to_stderr_by_default() {
+        StatusLogger statusLogger = new StatusLogger();
+        statusLogger.error("Test message");
+
+        assertEquals("", outBuf.toString());
+        assertThat(errBuf.toString()).contains("Test message");
+    }
+}

log4j-api/src/main/java/org/apache/logging/log4j/status/StatusLogger.java

@@ -531,7 +531,7 @@ private static final class InstanceHolder {
                 StatusLogger.class.getSimpleName(),
                 ParameterizedNoReferenceMessageFactory.INSTANCE,
                 Config.getInstance(),
-                new StatusConsoleListener(requireNonNull(Config.getInstance().fallbackListenerLevel)));
+                new StatusConsoleListener(requireNonNull(Config.getInstance().fallbackListenerLevel), System.err));
     }
 
     /**

src/changelog/.2.x.x/3665_fix_StatusLogger_writing_to_stdout.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="https://logging.apache.org/xml/ns"
+       xsi:schemaLocation="https://logging.apache.org/xml/ns https://logging.apache.org/xml/ns/log4j-changelog-0.xsd"
+       type="fixed">
+  <issue id="3665" link="https://github.com/apache/logging-log4j2/issues/3665"/>
+  <description format="asciidoc">
+    StatusLogger now writes to standard error by default. This fixes a regression introduced in 2.23.0.
+  </description>
+</entry>