Fix warning message; add test

microprofile/telemetry/pom.xml

@@ -91,6 +91,11 @@
             <optional>true</optional>
         </dependency>
         <!-- testing -->
+        <dependency>
+            <groupId>io.helidon.logging</groupId>
+            <artifactId>helidon-logging-jul</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>io.helidon.common.testing</groupId>
             <artifactId>helidon-common-testing-junit5</artifactId>

microprofile/telemetry/src/main/java/io/helidon/microprofile/telemetry/HelidonTelemetryContainerFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2023, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -106,9 +106,9 @@ class HelidonTelemetryContainerFilter implements ContainerRequestFilter, Contain
             LOGGER.log(System.Logger.Level.WARNING,
                        String.format("""
                                Current OpenTelemetry semantic conventions include the HTTP method as part of REST span
-                               names. Your configuration does not set mp.%s to true, so your service uses the legacy span name
+                               names. Your configuration does not set %s to true, so your service uses the legacy span name
                                format which excludes the HTTP method. This feature is deprecated and marked for removal in a
-                               future major release of Helidon. Consider adding a setting of mp.%1$s to 'true' in your
+                               future major release of Helidon. Consider adding a setting of %1$s to 'true' in your
                                configuration to migrate to the current conventions.""",
                                SPAN_NAME_INCLUDES_METHOD));
         }

microprofile/telemetry/src/test/java/io/helidon/microprofile/telemetry/MemoryLogHandler.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2025 Oracle and/or its affiliates.
+ *
+ * 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 io.helidon.microprofile.telemetry;
+
+import java.io.ByteArrayOutputStream;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
+import java.util.logging.LogRecord;
+import java.util.logging.StreamHandler;
+
+public class MemoryLogHandler extends StreamHandler {
+
+    private final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+
+    private static MemoryLogHandler create() {
+        try {
+            return new MemoryLogHandler();
+        } catch (UnsupportedEncodingException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public MemoryLogHandler() throws UnsupportedEncodingException {
+        setOutputStream(outputStream);
+        setEncoding(StandardCharsets.UTF_8.name());
+    }
+
+    @Override
+    public synchronized void publish(LogRecord record) {
+        super.publish(record);
+        flush();        // forces flush on writer
+    }
+
+    public String logAsString() {
+        return outputStream.toString(StandardCharsets.UTF_8);
+    }
+}

microprofile/telemetry/src/test/java/io/helidon/microprofile/telemetry/WithSpanUsingLegacySpanNameTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2024, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,25 +15,54 @@
  */
 package io.helidon.microprofile.telemetry;
 
+import java.io.UnsupportedEncodingException;
+import java.util.logging.Handler;
+import java.util.logging.Logger;
 import java.util.stream.Stream;
 
 import io.helidon.microprofile.testing.junit5.AddConfig;
 
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+
 @AddConfig(key = HelidonTelemetryContainerFilter.SPAN_NAME_INCLUDES_METHOD,
            value = "false")
 class WithSpanUsingLegacySpanNameTest extends WithSpanTestBase {
 
+    private static Logger logger = Logger.getLogger(HelidonTelemetryContainerFilter.class.getName());
+    private static MemoryLogHandler memoryLogHandler;
+
+    @BeforeAll
+    static void setup() {
+        for (Handler handler : logger.getHandlers()) {
+            if (handler instanceof MemoryLogHandler logHandler) {
+                memoryLogHandler = logHandler;
+            }
+        }
+    }
+
     @ParameterizedTest()
     @MethodSource()
-    void testDefaultAppSpanNameFromPath(SpanPathTestInfo spanPathTestInfo) {
+    void testDefaultAppSpanNameFromPath(SpanPathTestInfo spanPathTestInfo) throws UnsupportedEncodingException {
+
         testSpanNameFromPath(spanPathTestInfo);
+
+        // @Deprecated(forRemoval = true) in 5.1 remove the following:
+        assertThat("Log output",
+                   memoryLogHandler.logAsString(),
+                   containsString("does not set " + HelidonTelemetryContainerFilter.SPAN_NAME_INCLUDES_METHOD));
+        // end of removal
+
+
     }
 
     static Stream<SpanPathTestInfo> testDefaultAppSpanNameFromPath() {
         return Stream.of(new SpanPathTestInfo("traced", "/traced"),
                          new SpanPathTestInfo("traced/sub/data", "/traced/sub/{name}"));
     }
+
 }

microprofile/telemetry/src/test/resources/logging-test.properties

@@ -0,0 +1,27 @@
+#
+# Copyright (c) 2025 Oracle and/or its affiliates.
+#
+# 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.
+#
+handlers=java.util.logging.ConsoleHandler
+java.util.logging.ConsoleHandler.level=FINEST
+java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter
+java.util.logging.SimpleFormatter.format=%1$tH:%1$tM:%1$tS %4$s %3$s %5$s%6$s%n
+# Global logging level. Can be overridden by specific loggers
+.level=INFO
+
+io.helidon.microprofile.telemetry.MemoryLogHandler.level=INFO
+io.helidon.microprofile.telemetry.MemoryLogHandler.append=false
+io.helidon.microprofile.telemetry.HelidonTelemetryContainerFilter.level=INFO
+io.helidon.microprofile.telemetry.HelidonTelemetryContainerFilter.useParentHandlers=false
+io.helidon.microprofile.telemetry.HelidonTelemetryContainerFilter.handlers=io.helidon.microprofile.telemetry.MemoryLogHandler