feedback: added comments, move slf4j dep to each module inside gax.

Author: zhumin8

.github/workflows/ci.yaml

@@ -259,7 +259,7 @@ jobs:
             --batch-mode \
             --no-transfer-progress
       # The `slf4j2_logback` profile brings logging dependency and compiles logging tests, require env var to be set
-      - name: Showcase integration tests - Logging 2x
+      - name: Showcase integration tests - Logging SLF4J 2.x
         working-directory: showcase
         run: |
           mvn clean verify -P '!showcase,enable-integration-tests,loggingTestBase,slf4j2_logback' \
@@ -269,7 +269,7 @@ jobs:
         env:
           GOOGLE_SDK_JAVA_LOGGING: true
     # The `slf4j1_logback` profile brings logging dependency and compiles logging tests, require env var to be set
-      - name: Showcase integration tests - Logging 1x
+      - name: Showcase integration tests - Logging SLF4J 1.x
         working-directory: showcase
         run: |
           mvn clean verify -P '!showcase,enable-integration-tests,loggingTestBase,slf4j1_logback' \

gax-java/gax-grpc/pom.xml

@@ -92,6 +92,12 @@
       <artifactId>auto-value-annotations</artifactId>
       <scope>provided</scope>
     </dependency>
+    <!--    Logging dependency    -->
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <optional>true</optional>
+    </dependency>
 
     <!-- test dependencies -->
     <dependency>

gax-java/gax-httpjson/pom.xml

@@ -78,6 +78,12 @@
       <artifactId>auto-value-annotations</artifactId>
       <scope>provided</scope>
     </dependency>
+    <!--    Logging dependency    -->
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <optional>true</optional>
+    </dependency>
 
     <!-- test dependencies -->
     <dependency>

gax-java/gax/pom.xml

@@ -73,6 +73,12 @@
       <artifactId>opentelemetry-api</artifactId>
       <optional>true</optional>
     </dependency>
+    <!--    Logging dependency    -->
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <optional>true</optional>
+    </dependency>
   </dependencies>
 
   <build>

gax-java/pom.xml

@@ -172,12 +172,6 @@
 
 
   <dependencies>
-    <!--    Logging dependency    -->
-    <dependency>
-      <groupId>org.slf4j</groupId>
-      <artifactId>slf4j-api</artifactId>
-      <optional>true</optional>
-    </dependency>
     <!-- Test Dependencies -->
     <dependency>
       <groupId>org.junit.jupiter</groupId>

showcase/gapic-showcase/pom.xml

@@ -310,7 +310,8 @@
     </profile>
     <profile>
       <id>disabledLogging</id>
-      <!--   Only compile test to run when   GOOGLE_SDK_JAVA_LOGGING=!true -->
+      <!--   Only compile test to run when  GOOGLE_SDK_JAVA_LOGGING=!true -->
+      <!--   To verify logging correctly turned off when logging deps present -->
       <activation>
         <property>
           <name>disable_logging</name>