Renamed log4j appender module

spring-data-mongodb-log4j/src/main/java/org/springframework/data/document/mongodb/log4j/MongoLog4jAppender.java

@@ -162,14 +162,15 @@ public class MongoLog4jAppender extends AppenderSkeleton {
     dbo.put(MESSAGE, event.getRenderedMessage());
 
     // Insert the document
+    String coll;
     if (null == collection) {
       // Use the category name
-      collection = event.getLogger().getName();
+      coll = event.getLogger().getName();
     } else {
       Calendar now = Calendar.getInstance();
-      collection = String.format(collection,
+      coll = String.format(collection,
           now.get(Calendar.YEAR),
-          now.get(Calendar.MONTH),
+          now.get(Calendar.MONTH + 1),
           now.get(Calendar.DAY_OF_MONTH),
           now.get(Calendar.HOUR_OF_DAY),
           event.getLevel().toString(),
@@ -182,7 +183,7 @@ public class MongoLog4jAppender extends AppenderSkeleton {
     } else {
       wc = infoOrLowerWriteConcern;
     }
-    db.getCollection(collection).insert(dbo, wc);
+    db.getCollection(coll).insert(dbo, wc);
   }
 
   public void close() {

spring-data-mongodb-log4j/src/test/resources/log4j.properties

@@ -6,6 +6,7 @@ log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - <%m>%n
 log4j.appender.stdout.host = localhost
 log4j.appender.stdout.port = 27017
 log4j.appender.stdout.database = logs
+log4j.appender.stdout.collection = %1$4d%2$02d%3$02d
 log4j.appender.stdout.applicationId = my.application
 log4j.appender.stdout.warnOrHigherWriteConcern = FSYNC_SAFE