Use Log4J classes for custom logging

Align the use of custom loggers with the pattern used by
PluginLogFile in Gerrit.

This also removes the use of SLF4J which isn't used in Gerrit
anymore.

Change-Id: Ie622050124841cad1560689bc2f101a62a87481b
diff --git a/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLogger.java b/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLogger.java
index 7547cb7..3b4dbb2 100644
--- a/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLogger.java
+++ b/src/main/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLogger.java
@@ -29,6 +29,8 @@
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import org.apache.log4j.LogManager;
+import org.apache.log4j.Logger;
 import org.apache.log4j.PatternLayout;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.lib.Constants;
@@ -37,8 +39,6 @@
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Implementation of SharedRefLogger for Log4j. Logs to 'sharedref_log' file
@@ -66,7 +66,7 @@
   public Log4jSharedRefLogger(SystemLog systemLog, GitRepositoryManager gitRepositoryManager) {
     super(systemLog, LOG_NAME, new PatternLayout("[%d{ISO8601}] [%t] %-5p : %m%n"));
     this.gitRepositoryManager = gitRepositoryManager;
-    sharedRefDBLog = LoggerFactory.getLogger(LOG_NAME);
+    sharedRefDBLog = LogManager.getLogger(LOG_NAME);
   }
 
   /**
diff --git a/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLoggerTest.java b/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLoggerTest.java
index 2c89091..346edd7 100644
--- a/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLoggerTest.java
+++ b/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/Log4jSharedRefLoggerTest.java
@@ -29,6 +29,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import org.apache.log4j.LogManager;
+import org.apache.log4j.Logger;
 import org.apache.log4j.PatternLayout;
 import org.apache.log4j.WriterAppender;
 import org.eclipse.jgit.lib.ObjectId;
@@ -36,8 +37,6 @@
 import org.eclipse.jgit.lib.Repository;
 import org.junit.Before;
 import org.junit.Test;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class Log4jSharedRefLoggerTest extends AbstractDaemonTest {
 
@@ -152,9 +151,9 @@
   }
 
   private Logger logWriterLogger() {
-    org.apache.log4j.Logger logger = LogManager.getLogger("logWriterLogger");
+    Logger logger = LogManager.getLogger("logWriterLogger");
     logger.addAppender(new WriterAppender(new PatternLayout("%m"), logWriter));
-    return LoggerFactory.getLogger("logWriterLogger");
+    return logger;
   }
 
   private static Path newPath() throws IOException {