Use SLF4J's version of the commons-logging bindings. Only include SLF4J's Log4J back-end for actual applications, e.g. Node. (#350)

build.gradle

@@ -19,6 +19,7 @@ buildscript {
     ext.jersey_version = '2.25'
     ext.jolokia_version = '2.0.0-M3'
     ext.assertj_version = '3.6.1'
+    ext.slf4j_version = '1.7.22'
     ext.log4j_version = '2.7'
     ext.bouncycastle_version = '1.56'
     ext.guava_version = '19.0'

client/build.gradle

@@ -47,10 +47,6 @@ dependencies {
     compile project(":core")
     compile project(':node')
 
-    // Log4J: logging framework (with SLF4J bindings)
-    compile "org.apache.logging.log4j:log4j-slf4j-impl:${log4j_version}"
-    compile "org.apache.logging.log4j:log4j-core:${log4j_version}"
-
     compile "com.google.guava:guava:$guava_version"
 
     // ReactFX: Functional reactive UI programming.

core/build.gradle

@@ -50,10 +50,12 @@ dependencies {
     // Thread safety annotations
     compile "com.google.code.findbugs:jsr305:3.0.1"
 
-    // Log4J: logging framework (with SLF4J bindings)
-    compile "org.apache.logging.log4j:log4j-slf4j-impl:${log4j_version}"
+    // Log4J: logging framework (ONLY explicitly referenced by net.corda.core.utilities.Logging.kt)
     compile "org.apache.logging.log4j:log4j-core:${log4j_version}"
 
+    // SLF4J: commons-logging bindings for a SLF4J back end
+    compile "org.slf4j:jcl-over-slf4j:$slf4j_version"
+
     // AssertJ: for fluent assertions for testing
     testCompile "org.assertj:assertj-core:${assertj_version}"
 
@@ -96,3 +98,9 @@ dependencies {
     // Requery: SQL based query & persistence for Kotlin
     compile "io.requery:requery-kotlin:$requery_version"
 }
+
+configurations.compile {
+    // We want to use SLF4J's version of these binding: jcl-over-slf4j
+    // Remove any transitive dependency on Apache's version.
+    exclude group: 'commons-logging', module: 'commons-logging'
+}

node/build.gradle

@@ -73,7 +73,6 @@ dependencies {
 
     // Log4J: logging framework (with SLF4J bindings)
     compile "org.apache.logging.log4j:log4j-slf4j-impl:${log4j_version}"
-    compile "org.apache.logging.log4j:log4j-core:${log4j_version}"
     compile "org.apache.logging.log4j:log4j-web:${log4j_version}"
 
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
@@ -109,8 +108,6 @@ dependencies {
     // TODO: Remove this dependency and the code that requires it
     compile "commons-fileupload:commons-fileupload:1.3.2"
 
-    // Force commons logging to version 1.2 to override Artemis, which pulls in 1.1.3 (ARTEMIS-424)
-    compile "commons-logging:commons-logging:1.2"
     compile "com.fasterxml.jackson.core:jackson-annotations:${jackson_version}"
 
     // Coda Hale's Metrics: for monitoring of key statistics
@@ -170,6 +167,12 @@ dependencies {
     integrationTestCompile "junit:junit:$junit_version"
 }
 
+configurations.compile {
+    // We want to use SLF4J's version of these binding: jcl-over-slf4j
+    // Remove any transitive dependency on Apache's version.
+    exclude group: 'commons-logging', module: 'commons-logging'
+}
+
 task integrationTest(type: Test) {
     testClassesDir = sourceSets.integrationTest.output.classesDir
     classpath = sourceSets.integrationTest.runtimeClasspath

test-utils/build.gradle

@@ -28,19 +28,12 @@ dependencies {
     compile project(':node')
     compile project(':node:webserver')
 
-    // Log4J: logging framework (with SLF4J bindings)
-    compile "org.apache.logging.log4j:log4j-slf4j-impl:${log4j_version}"
-    compile "org.apache.logging.log4j:log4j-core:${log4j_version}"
-
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
     compile "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
 
     compile "com.google.guava:guava:$guava_version"
 
-    // Force commons logging to version 1.2 to override Artemis, which pulls in 1.1.3 (ARTEMIS-424)
-    compile "commons-logging:commons-logging:1.2"
-
     // Unit testing helpers.
     compile "junit:junit:$junit_version"
 
@@ -50,3 +43,9 @@ dependencies {
     // OkHTTP: Simple HTTP library.
     compile "com.squareup.okhttp3:okhttp:$okhttp_version"
 }
+
+configurations.compile {
+    // We want to use SLF4J's version of these bindings: jcl-over-slf4j
+    // Remove any transitive dependency on Apache's version.
+    exclude group: 'commons-logging', module: 'commons-logging'
+}