Apply consistent log argument quoting for sigle- and multi-valued args
diff --git a/maven-core/src/main/java/org/apache/maven/graph/DefaultGraphBuilder.java b/maven-core/src/main/java/org/apache/maven/graph/DefaultGraphBuilder.java
index 14f114d..797cbe2 100644
--- a/maven-core/src/main/java/org/apache/maven/graph/DefaultGraphBuilder.java
+++ b/maven-core/src/main/java/org/apache/maven/graph/DefaultGraphBuilder.java
@@ -458,7 +458,7 @@
 
                     if ( projectsMap.containsKey( pluginKey ) )
                     {
-                        LOGGER.warn( "{} uses {} as extensions, which is not possible within the same reactor build. "
+                        LOGGER.warn( "'{}' uses '{}' as extension which is not possible within the same reactor build. "
                             + "This plugin was pulled from the local repository!", project.getName(), plugin.getKey() );
                     }
                 }
diff --git a/maven-core/src/main/java/org/apache/maven/project/MavenProject.java b/maven-core/src/main/java/org/apache/maven/project/MavenProject.java
index 94dc70a..958df1e 100644
--- a/maven-core/src/main/java/org/apache/maven/project/MavenProject.java
+++ b/maven-core/src/main/java/org/apache/maven/project/MavenProject.java
@@ -936,7 +936,7 @@
         int index = attachedArtifacts.indexOf( artifact );
         if ( index >= 0 )
         {
-            LOGGER.warn( "artifact {} already attached, replace previous instance", artifact );
+            LOGGER.warn( "artifact '{}' already attached, replacing previous instance", artifact );
             attachedArtifacts.set( index, artifact );
         }
         else
diff --git a/maven-core/src/main/java/org/apache/maven/project/collector/DefaultProjectsSelector.java b/maven-core/src/main/java/org/apache/maven/project/collector/DefaultProjectsSelector.java
index 3776c6f..d341d0a 100644
--- a/maven-core/src/main/java/org/apache/maven/project/collector/DefaultProjectsSelector.java
+++ b/maven-core/src/main/java/org/apache/maven/project/collector/DefaultProjectsSelector.java
@@ -74,7 +74,7 @@
             if ( !result.getProblems().isEmpty() && LOGGER.isWarnEnabled() )
             {
                 LOGGER.warn( "" );
-                LOGGER.warn( "Some problems were encountered while building the effective model for {}",
+                LOGGER.warn( "Some problems were encountered while building the effective model for '{}'",
                         result.getProject().getId() );
 
                 for ( ModelProblem problem : result.getProblems() )
diff --git a/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java b/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java
index 1aab11c..88c1b8c 100644
--- a/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java
+++ b/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java
@@ -76,7 +76,7 @@
             }
             else
             {
-                logger.debug( "Multi module project collection failed: {}"
+                logger.debug( "Multi module project collection failed:{}"
                         + "Detected a POM file next to a .mvn folder in a parent directory ({}). "
                         + "Maven assumed that POM file to be the parent of the requested project ({}), but it turned "
                         + "out that it was not. Another project collection strategy will be executed as result.",
@@ -91,7 +91,7 @@
 
             if ( fallThrough )
             {
-                logger.debug( "Multi module project collection failed: {}"
+                logger.debug( "Multi module project collection failed:{}"
                         + "Detected that one of the modules of this multi module project uses another module as "
                         + "plugin extension which still needed to be built. This is not possible within the same "
                         + "reactor build. Another project collection strategy will be executed as result.",
@@ -115,8 +115,8 @@
             if ( !multiModuleProjectPom.exists() )
             {
                 logger.info( "Maven detected that the requested POM file is part of a multi module project, "
-                        + "but could not find a pom.xml file in the multi module root directory: '"
-                        + request.getMultiModuleProjectDirectory() + "'. " );
+                        + "but could not find a pom.xml file in the multi module root directory '{}'.",
+                        request.getMultiModuleProjectDirectory() );
                 logger.info( "The reactor is limited to all projects under: " + request.getPom().getParent() );
                 return request.getPom();
             }
diff --git a/maven-embedder/src/main/java/org/apache/maven/cli/MavenCli.java b/maven-embedder/src/main/java/org/apache/maven/cli/MavenCli.java
index 055e89e..7afe073 100644
--- a/maven-embedder/src/main/java/org/apache/maven/cli/MavenCli.java
+++ b/maven-embedder/src/main/java/org/apache/maven/cli/MavenCli.java
@@ -790,7 +790,7 @@
         }
         catch ( Exception e )
         {
-            slf4jLogger.warn( "Failed to read extensions descriptor {}: {}", extensionsFile, e.getMessage() );
+            slf4jLogger.warn( "Failed to read extensions descriptor from '{}'", extensionsFile, e );
         }
         return Collections.emptyList();
     }
@@ -818,11 +818,11 @@
 
             extRealm.setParentRealm( coreRealm );
 
-            slf4jLogger.debug( "Populating class realm {}", extRealm.getId() );
+            slf4jLogger.debug( "Populating class realm '{}'", extRealm.getId() );
 
             for ( File file : extClassPath )
             {
-                slf4jLogger.debug( "  Included {}", file );
+                slf4jLogger.debug( "  included '{}'", file );
 
                 extRealm.addURL( file.toURI().toURL() );
             }
@@ -871,7 +871,7 @@
             {
                 File file = resolveFile( new File( jar ), cliRequest.workingDirectory );
 
-                slf4jLogger.debug( "  Included {}", file );
+                slf4jLogger.debug( "  included '{}'", file );
 
                 jars.add( file );
             }
@@ -1006,12 +1006,12 @@
 
             if ( !cliRequest.showErrors )
             {
-                slf4jLogger.error( "To see the full stack trace of the errors, re-run Maven with the {} switch.",
+                slf4jLogger.error( "To see the full stack trace of the errors, re-run Maven with the '{}' switch.",
                         buffer().strong( "-e" ) );
             }
             if ( !slf4jLogger.isDebugEnabled() )
             {
-                slf4jLogger.error( "Re-run Maven using the {} switch to enable full debug logging.",
+                slf4jLogger.error( "Re-run Maven using the '{}' switch to enable full debug logging.",
                         buffer().strong( "-X" ) );
             }
 
@@ -1299,9 +1299,9 @@
 
         eventSpyDispatcher.onEvent( toolchainsRequest );
 
-        slf4jLogger.debug( "Reading global toolchains from {}",
+        slf4jLogger.debug( "Reading global toolchains from '{}'",
                 getLocation( toolchainsRequest.getGlobalToolchainsSource(), globalToolchainsFile ) );
-        slf4jLogger.debug( "Reading user toolchains from {}",
+        slf4jLogger.debug( "Reading user toolchains from '{}'",
                 getLocation( toolchainsRequest.getUserToolchainsSource(), userToolchainsFile ) );
 
         ToolchainsBuildingResult toolchainsResult = toolchainsBuilder.build( toolchainsRequest );
diff --git a/maven-embedder/src/main/java/org/apache/maven/cli/configuration/SettingsXmlConfigurationProcessor.java b/maven-embedder/src/main/java/org/apache/maven/cli/configuration/SettingsXmlConfigurationProcessor.java
index 5c5ce4e..f57d782 100644
--- a/maven-embedder/src/main/java/org/apache/maven/cli/configuration/SettingsXmlConfigurationProcessor.java
+++ b/maven-embedder/src/main/java/org/apache/maven/cli/configuration/SettingsXmlConfigurationProcessor.java
@@ -137,9 +137,9 @@
             request.getEventSpyDispatcher().onEvent( settingsRequest );
         }
 
-        logger.debug( "Reading global settings from {}",
+        logger.debug( "Reading global settings from '{}'",
             getLocation( settingsRequest.getGlobalSettingsSource(), settingsRequest.getGlobalSettingsFile() ) );
-        logger.debug( "Reading user settings from {}",
+        logger.debug( "Reading user settings from '{}'",
             getLocation( settingsRequest.getUserSettingsSource(), settingsRequest.getUserSettingsFile() ) );
 
         SettingsBuildingResult settingsResult = settingsBuilder.build( settingsRequest );
diff --git a/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java b/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java
index f3cd858..24652d4 100644
--- a/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java
+++ b/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java
@@ -361,7 +361,7 @@
     {
         if ( logger.isWarnEnabled() )
         {
-            logger.warn( "Goal {} requires online mode for execution but Maven is currently offline, skipping",
+            logger.warn( "Goal '{}' requires online mode for execution but Maven is currently offline, skipping",
                     event.getMojoExecution().getGoal() );
         }
     }