diff --git a/oaipmh-core/pom.xml b/oaipmh-core/pom.xml
index efbe416e1180a5d587ece52f9b7acb453d165bdd..c7902dddaae2e736f372b3d55f7dd4ff470d4bc7 100644
--- a/oaipmh-core/pom.xml
+++ b/oaipmh-core/pom.xml
@@ -68,16 +68,6 @@
 			<version>${junit.version}</version>
 			<scope>test</scope>
 		</dependency>
-		<!-- <dependency> -->
-		<!-- <groupId>org.apache.logging.log4j</groupId> -->
-		<!-- <artifactId>log4j-api</artifactId> -->
-		<!-- <version>${log4j.version}</version> -->
-		<!-- </dependency> -->
-		<!-- <dependency> -->
-		<!-- <groupId>org.apache.logging.log4j</groupId> -->
-		<!-- <artifactId>log4j-core</artifactId> -->
-		<!-- <version>${log4j.version}</version> -->
-		<!-- </dependency> -->
 		<dependency>
 			<groupId>org.elasticsearch.client</groupId>
 			<artifactId>elasticsearch-rest-high-level-client</artifactId>
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/DublinCoreFieldLoader.java b/oaipmh-core/src/main/java/info/textgrid/middleware/DublinCoreFieldLoader.java
index b1ded25337031293c42c03ec99bfcdf5d150a4be..0e03d3ad69282867b79093d808e3c2c325469bc6 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/DublinCoreFieldLoader.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/DublinCoreFieldLoader.java
@@ -4,9 +4,8 @@ import java.text.ParseException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.logging.Logger;
 import javax.xml.datatype.DatatypeConfigurationException;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.search.SearchHit;
 
@@ -32,16 +31,16 @@ public class DublinCoreFieldLoader {
   // STATICS
   // **
 
-  private static Log log = LogFactory.getLog(DublinCoreFieldLoader.class);
+  private static Logger log = Logger.getLogger(DublinCoreFieldLoader.class.getName());
 
   /**
    * This function takes the results of the ElasticSearch request and fills the String-Lists with
-   * the specific values for the dublin core field
+   * the specific values for the Dublin Core field
    * 
    * @param responseOfGetRequest result of the ElasticSearch request from a getRequest (Single
    *        Result)
-   * @param fields String List for the specific dublin core field
-   * @return String List containing the values for the specific dublin core field
+   * @param fields String List for the specific Dublin Core field
+   * @return String List containing the values for the specific Dublin Core field
    */
 
   /**
@@ -69,12 +68,12 @@ public class DublinCoreFieldLoader {
         } catch (ParseException e) {
           // FIXME DO NOT USE INVALID DATE HERE!
           dates.add(responseWorkValues.getField(field).getValue().toString());
-          log.debug("Tried to parse date value: "
+          log.fine("tried to parse date value: "
               + responseWorkValues.getField(field).getValue().toString());
         } catch (DatatypeConfigurationException e) {
           // FIXME DO NOT USE INVALID DATE HERE!
           dates.add(responseWorkValues.getField(field).getValue().toString());
-          log.debug("Tried to configure date value: "
+          log.fine("tried to configure date value: "
               + responseWorkValues.getField(field).getValue().toString());
         }
       }
@@ -139,6 +138,7 @@ public class DublinCoreFieldLoader {
                   e.printStackTrace();
                 }
                 if (nestedMap.get(requestedField[i]) instanceof Map<?, ?>) {
+                  // TODO Comment or remove code!
                 }
               }
               if (i == requestedField.length - 1 &&
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/IdentifierListDelivererIDIOM.java b/oaipmh-core/src/main/java/info/textgrid/middleware/IdentifierListDelivererIDIOM.java
index 10e44f99c741b014048a1e2167f8733fefdaa25d..71f292cb9c61a120ddfa99249895092a583ef8c3 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/IdentifierListDelivererIDIOM.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/IdentifierListDelivererIDIOM.java
@@ -4,8 +4,6 @@ import java.io.IOException;
 import java.text.ParseException;
 import java.util.Hashtable;
 import java.util.Map;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchScrollRequest;
@@ -29,7 +27,6 @@ public class IdentifierListDelivererIDIOM extends IdentifierListDelivererAbstrac
   // STATICS
   // **
 
-  private static Log log = LogFactory.getLog(IdentifierListDelivererIDIOM.class);
   protected static Map<String, Integer> cursorCollector = new Hashtable<String, Integer>();
 
   // **
@@ -53,6 +50,7 @@ public class IdentifierListDelivererIDIOM extends IdentifierListDelivererAbstrac
    * @see info.textgrid.middleware.IdentifierListDelivererAbstract#processIdentifierList(java.lang.
    * String, java.lang.String, java.lang.String, java.lang.String)
    */
+  @Override
   public ListIdentifiersType processIdentifierList(final String from, final String to,
       final String set, final String resumptionToken) throws ParseException, IOException {
 
@@ -65,15 +63,15 @@ public class IdentifierListDelivererIDIOM extends IdentifierListDelivererAbstrac
     BoolQueryBuilder both;
 
     RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery("lastModified").from(from).to(to);
-    
+
     BoolQueryBuilder test = QueryBuilders.boolQuery()
         .must(QueryBuilders.matchPhraseQuery("project.id",
-        "TGPR-0e926f53-1aba-d415-ecf6-539edcd8a318"));
+            "TGPR-0e926f53-1aba-d415-ecf6-539edcd8a318"));
 
     BoolQueryBuilder artefact = QueryBuilders.boolQuery()
         .must(QueryBuilders.matchPhraseQuery("format", "text/tg.inputform+rdf+xml"))
         .must(QueryBuilders.matchPhraseQuery("notes", "ARTEFACT"));
-        
+
     BoolQueryBuilder conedakor = QueryBuilders.boolQuery()
         .must(QueryBuilders.matchPhraseQuery("format", "application/json"))
         .must(QueryBuilders.matchPhraseQuery("notes", "ConedaKorMediumData"));
@@ -82,7 +80,7 @@ public class IdentifierListDelivererIDIOM extends IdentifierListDelivererAbstrac
     both = QueryBuilders.boolQuery().should(artefact).should(conedakor);
 
     BoolQueryBuilder bla = QueryBuilders.boolQuery().must(rangeQuery)
-    .must(test.filter(both));
+        .must(test.filter(both));
 
     recordFilterForClassicMayan = bla;
 
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/OAIPMHImpl.java b/oaipmh-core/src/main/java/info/textgrid/middleware/OAIPMHImpl.java
index 9f35a359ac573d5df580ec1fdf8c6a99a3a8ab80..de18f8a2d5fdf092c6bc84112a543a2548c03f84 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/OAIPMHImpl.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/OAIPMHImpl.java
@@ -5,14 +5,13 @@ import java.io.StringWriter;
 import java.text.ParseException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.logging.Logger;
 import javax.xml.bind.JAXBContext;
 import javax.xml.bind.JAXBElement;
 import javax.xml.bind.JAXBException;
 import javax.xml.bind.Marshaller;
 import javax.xml.datatype.DatatypeConfigurationException;
 import javax.xml.datatype.XMLGregorianCalendar;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 
 import info.textgrid.middleware.oaipmh.GetRecordType;
 import info.textgrid.middleware.oaipmh.IdentifyType;
@@ -55,7 +54,7 @@ public class OAIPMHImpl implements OAIPMHProducer {
   // STATICS
   // **
 
-  private static Log log = LogFactory.getLog(OAIPMHImpl.class);
+  private static Logger log = Logger.getLogger(OAIPMHImpl.class.getName());
   private static ObjectFactory obf = new ObjectFactory();
 
   // **
@@ -788,9 +787,9 @@ public class OAIPMHImpl implements OAIPMHProducer {
           .convertDateFormat(OAIPMHUtilities.getXMLGregorianCalendarNow().toString());
       response.setResponseDate(convertedDateFormat);
     } catch (ParseException e) {
-      log.debug("can not parse date format");
+      log.severe("can not parse date format");
     } catch (DatatypeConfigurationException e) {
-      log.debug("datatype configuration failed");
+      log.severe("datatype configuration failed");
     }
 
     // Convert the request values.
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDATACITE.java b/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDATACITE.java
index 190e26a5852632719a7043453dd0c00bf36d592d..6d2200175eb952e39daf4b60268435cf44ad415f 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDATACITE.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDATACITE.java
@@ -6,9 +6,8 @@ import java.io.InputStream;
 import java.text.ParseException;
 import java.util.List;
 import java.util.Properties;
+import java.util.logging.Logger;
 import javax.xml.datatype.DatatypeConfigurationException;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.common.Strings;
 import org.json.JSONObject;
 import org.springframework.stereotype.Component;
@@ -59,7 +58,7 @@ import info.textgrid.middleware.oaipmh.Resource.Titles.Title;
 public class RecordDelivererDATACITE extends RecordDelivererAbstract {
 
   // Logger for errors and info
-  private static Log log = LogFactory.getLog(RecordDelivererDATACITE.class);
+  private static Logger log = Logger.getLogger(RecordDelivererDATACITE.class.getName());
 
   // Container object for the result of the elasticsearch request. This object contains the source
   // of the response.
@@ -103,6 +102,7 @@ public class RecordDelivererDATACITE extends RecordDelivererAbstract {
    * 
    * @see info.textgrid.middleware.RecordDelivererInterface#getRecordById(java.lang.String)
    */
+  @Override
   public GetRecordType getRecordById(final String idInElasticSearchIndex)
       throws ParseException, DatatypeConfigurationException, IOException {
 
@@ -724,7 +724,7 @@ public class RecordDelivererDATACITE extends RecordDelivererAbstract {
           dateInOpenAireRecord.setDateType(DateType.UPDATED);
         }
       } catch (ParseException | DatatypeConfigurationException e) {
-        log.error("Could not parse date field: " + e.getMessage());
+        log.severe("could not parse date field: " + e.getMessage());
       }
 
       dates.getDate().add(dateInOpenAireRecord);
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDC.java b/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDC.java
index be20b1849a8915116f2abfd5e0b7d731958056ff..fabcf97a5834272258913a66c510bb4dbff9d7b7 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDC.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/RecordDelivererDC.java
@@ -2,9 +2,8 @@ package info.textgrid.middleware;
 
 import java.io.IOException;
 import java.text.ParseException;
+import java.util.logging.Logger;
 import javax.xml.datatype.DatatypeConfigurationException;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.common.Strings;
 import org.json.JSONObject;
@@ -21,7 +20,7 @@ import info.textgrid.middleware.oaipmh.RecordType;
 @Component
 public class RecordDelivererDC extends RecordDelivererAbstract {
 
-  private static Log log = LogFactory.getLog(RecordDelivererDC.class);
+  private static Logger log = Logger.getLogger(RecordDelivererDC.class.getName());
 
   /**
    * @param textgrid
@@ -36,6 +35,7 @@ public class RecordDelivererDC extends RecordDelivererAbstract {
    * 
    * @see info.textgrid.middleware.RecordDelivererInterface#getRecordById(java.lang.String)
    */
+  @Override
   public GetRecordType getRecordById(String id)
       throws ParseException, DatatypeConfigurationException {
 
@@ -61,7 +61,7 @@ public class RecordDelivererDC extends RecordDelivererAbstract {
     } catch (IOException e1) {
       // TODO Auto-generated catch block
       e1.printStackTrace();
-      log.error("Could not fetch the result of ElasticSearch");
+      log.severe("could not fetch the result of elasticsearch");
     }
 
     if (esResultObject.isExists()) {
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/RecordListDelivererDATACITE.java b/oaipmh-core/src/main/java/info/textgrid/middleware/RecordListDelivererDATACITE.java
index 794bb4f4174c8c1eec9c42ac9b9a11456b842db4..d87735bed732cbb3be6bb6a9ff651f859e697fc8 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/RecordListDelivererDATACITE.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/RecordListDelivererDATACITE.java
@@ -6,9 +6,8 @@ import java.util.ArrayList;
 import java.util.Hashtable;
 import java.util.List;
 import java.util.Map;
+import java.util.logging.Logger;
 import javax.xml.datatype.DatatypeConfigurationException;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchScrollRequest;
@@ -34,7 +33,7 @@ public class RecordListDelivererDATACITE extends RecordListDelivererAbstract {
   // STATICS
   // **
 
-  private static Log log = LogFactory.getLog(RecordListDelivererDATACITE.class);
+  private static Logger log = Logger.getLogger(RecordListDelivererDATACITE.class.getName());
   protected static Map<String, Integer> cursorCollector = new Hashtable<String, Integer>();
 
   /**
@@ -51,13 +50,14 @@ public class RecordListDelivererDATACITE extends RecordListDelivererAbstract {
    * @see info.textgrid.middleware.RecordListDelivererInterface#getRecords(java.lang.String,
    * java.lang.String, java.lang.String, java.lang.String)
    */
+  @Override
   public ListRecordsType getRecords(String from, String to, String set, String resumptionToken)
       throws ParseException, IOException {
 
     ListRecordsType openAireRecordList = new ListRecordsType();
 
     // Create one RecordDeliverer only, to configure all fields only ONCE.
-    // FIYME May be solved using spring configuration, but I do not know how!
+    // FIXME May be solved using spring configuration, but I do not know how!
     RecordDelivererDATACITE openAireRecord =
         new RecordDelivererDATACITE(this.textgrid, this.dariah);
     // Must be done here, as spring does not configure this bean if instantiated with "new".
@@ -237,7 +237,7 @@ public class RecordListDelivererDATACITE extends RecordListDelivererAbstract {
         try {
           cursorCollector.remove(resumptionToken);
         } catch (NullPointerException couldNotRemove) {
-          log.debug("Could not remove hash value: " + resumptionToken + " from hash map");
+          log.severe("could not remove hash value: " + resumptionToken + " from hash map");
         }
         this.resTokenForResponse.setValue("");
       } else {
diff --git a/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java b/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java
index 0567e0729f208acd8447d2dbb27a3f657bd77cc8..729f9a0327f86e5faa4d9db6de371aadd434f1e3 100644
--- a/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java
+++ b/oaipmh-core/src/main/java/info/textgrid/middleware/SetListDeliverer.java
@@ -2,8 +2,7 @@ package info.textgrid.middleware;
 
 import java.io.IOException;
 import java.util.Map.Entry;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
+import java.util.logging.Logger;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.client.RequestOptions;
@@ -27,7 +26,7 @@ import info.textgrid.middleware.oaipmh.SetType;
  */
 public class SetListDeliverer {
 
-  private static Log log = LogFactory.getLog(SetListDeliverer.class);
+  private static Logger log = Logger.getLogger(SetListDeliverer.class.getName());
 
   private static final int DH_SIZE = 100000;
 
@@ -119,7 +118,7 @@ public class SetListDeliverer {
 
     } catch (IOException e) {
       // TODO Auto-generated catch block
-      log.error(e.getMessage());
+      log.severe(e.getMessage());
       e.printStackTrace();
     }
 
diff --git a/oaipmh-core/src/test/java/info/textgrid/middleware/ClassicMayanTest.java b/oaipmh-core/src/test/java/info/textgrid/middleware/ClassicMayanTest.java
index eda8f96ab65a7879897f2f96474ff772c2b2a2f4..3ee7b137451ac5279cd7cb957d6e6c52f4220d77 100644
--- a/oaipmh-core/src/test/java/info/textgrid/middleware/ClassicMayanTest.java
+++ b/oaipmh-core/src/test/java/info/textgrid/middleware/ClassicMayanTest.java
@@ -19,54 +19,86 @@ import org.xml.sax.SAXException;
 
 import info.textgrid.middleware.oaipmh.OAIPMHtype;
 
+/**
+ *
+ */
 public class ClassicMayanTest {
-   
-    @Test
-    @Ignore
-    public void testGetRecord() throws JSONException, IOException, SAXException, ParseException, TransformerFactoryConfigurationError, TransformerException{
-        IDIOMImages imageList = new IDIOMImages();
-        Document document;
-        try {
-            document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
-            JAXB.marshal(imageList.getRecordById("11480"), new DOMResult(document));
-            imageList.printXML(document);
-        } catch (ParserConfigurationException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        }
-    }
 
-    @Test
-    @Ignore
-    public void testGetMediaList() throws JSONException, IOException, ParseException, SAXException, TransformerFactoryConfigurationError, TransformerException{
-        
-        IDIOMImages imageList = new IDIOMImages();
-        
-        imageList.setKindID("1");
-        imageList.setPerPage("100");
-        imageList.setPageNumber("1");
-
-        Document document;
-        try {
-            document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
-            JAXB.marshal(imageList.getRecords(null, null, null, null), new DOMResult(document));
-            imageList.printXML(document);
-        } catch (ParserConfigurationException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        }
+  /**
+   * @throws JSONException
+   * @throws IOException
+   * @throws SAXException
+   * @throws ParseException
+   * @throws TransformerFactoryConfigurationError
+   * @throws TransformerException
+   */
+  @Test
+  @Ignore
+  public void testGetRecord() throws JSONException, IOException, SAXException, ParseException,
+      TransformerFactoryConfigurationError, TransformerException {
+
+    IDIOMImages imageList = new IDIOMImages();
+    Document document;
+    try {
+      document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
+      JAXB.marshal(imageList.getRecordById("11480"), new DOMResult(document));
+      imageList.printXML(document);
+    } catch (ParserConfigurationException e) {
+      // TODO Auto-generated catch block
+      e.printStackTrace();
     }
+  }
+
+  /**
+   * @throws JSONException
+   * @throws IOException
+   * @throws ParseException
+   * @throws SAXException
+   * @throws TransformerFactoryConfigurationError
+   * @throws TransformerException
+   */
+  @Test
+  @Ignore
+  public void testGetMediaList() throws JSONException, IOException, ParseException, SAXException,
+      TransformerFactoryConfigurationError, TransformerException {
+
+    IDIOMImages imageList = new IDIOMImages();
 
-    @Test
-    @Ignore
-    public void testOAIPMHRequest() throws JSONException, IOException, ParseException, SAXException, TransformerFactoryConfigurationError, TransformerException{
-        OAIPMHtype request = new OAIPMHtype();
-        IDIOMImages imageList = new IDIOMImages();
-        
-        imageList.setKindID("1");
-        imageList.setPerPage("100");
-        imageList.setPageNumber("1");
-        //request.setListRecords(imageList.getAllMedia());
+    imageList.setKindID("1");
+    imageList.setPerPage("100");
+    imageList.setPageNumber("1");
 
+    Document document;
+    try {
+      document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
+      JAXB.marshal(imageList.getRecords(null, null, null, null), new DOMResult(document));
+      imageList.printXML(document);
+    } catch (ParserConfigurationException e) {
+      // TODO Auto-generated catch block
+      e.printStackTrace();
     }
+  }
+
+  /**
+   * @throws JSONException
+   * @throws IOException
+   * @throws ParseException
+   * @throws SAXException
+   * @throws TransformerFactoryConfigurationError
+   * @throws TransformerException
+   */
+  @Test
+  @Ignore
+  public void testOAIPMHRequest() throws JSONException, IOException, ParseException, SAXException,
+      TransformerFactoryConfigurationError, TransformerException {
+
+    OAIPMHtype request = new OAIPMHtype();
+    IDIOMImages imageList = new IDIOMImages();
+
+    imageList.setKindID("1");
+    imageList.setPerPage("100");
+    imageList.setPageNumber("1");
+    // request.setListRecords(imageList.getAllMedia());
+  }
+
 }