diff --git a/src/main/java/de/gwdg/metadataqa/marc/cli/QACli.java b/src/main/java/de/gwdg/metadataqa/marc/cli/QACli.java
index c12046897..22c20b034 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/cli/QACli.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/cli/QACli.java
@@ -5,29 +5,24 @@
 import de.gwdg.metadataqa.marc.CsvUtils;
 import de.gwdg.metadataqa.marc.Utils;
 import de.gwdg.metadataqa.marc.cli.parameters.CommonParameters;
-import de.gwdg.metadataqa.marc.cli.parameters.ValidatorParameters;
 import de.gwdg.metadataqa.marc.dao.record.BibliographicRecord;
 import de.gwdg.metadataqa.marc.utils.BibiographicPath;
 import de.gwdg.metadataqa.marc.utils.pica.path.PicaPath;
 import de.gwdg.metadataqa.marc.utils.pica.path.PicaPathParser;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.lang3.StringUtils;
-import org.apache.commons.lang3.time.DurationFormatUtils;
 
 import java.io.File;
 import java.io.IOException;
 import java.net.URISyntaxException;
-import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.nio.file.attribute.FileTime;
-import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
-import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/cli/SerialScore.java b/src/main/java/de/gwdg/metadataqa/marc/cli/SerialScore.java
index a37780540..ac69be619 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/cli/SerialScore.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/cli/SerialScore.java
@@ -20,7 +20,6 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.Serializable;
-import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/FormatterParameters.java b/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/FormatterParameters.java
index f89ee04a5..66f4fc253 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/FormatterParameters.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/FormatterParameters.java
@@ -25,6 +25,7 @@ public class FormatterParameters extends CommonParameters {
 
   private boolean isOptionSet = false;
 
+  @Override
   protected void setOptions() {
     if (!isOptionSet) {
       super.setOptions();
diff --git a/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/MarcToSolrParameters.java b/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/MarcToSolrParameters.java
index d19f2f15a..acf6d662c 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/MarcToSolrParameters.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/MarcToSolrParameters.java
@@ -19,6 +19,7 @@ public class MarcToSolrParameters extends CommonParameters {
   private int commitAt = DEFAULT_COMMIT_AT;
   private boolean indexFieldCounts = false;
 
+  @Override
   protected void setOptions() {
     if (!isOptionSet) {
       super.setOptions();
diff --git a/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/NetworkParameters.java b/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/NetworkParameters.java
index 87b8b355d..008f61433 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/NetworkParameters.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/cli/parameters/NetworkParameters.java
@@ -11,6 +11,7 @@ public class NetworkParameters extends CommonParameters implements Serializable
   private int groupLimit = 1000;
   private boolean isOptionSet;
 
+  @Override
   protected void setOptions() {
     if (!isOptionSet) {
       super.setOptions();
diff --git a/src/main/java/de/gwdg/metadataqa/marc/cli/utils/RecordIterator.java b/src/main/java/de/gwdg/metadataqa/marc/cli/utils/RecordIterator.java
index ec35633d9..072e4fcb7 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/cli/utils/RecordIterator.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/cli/utils/RecordIterator.java
@@ -16,7 +16,6 @@
 import de.gwdg.metadataqa.marc.utils.pica.PicaSchemaReader;
 import org.apache.commons.cli.HelpFormatter;
 import org.apache.commons.cli.Options;
-import org.apache.commons.lang3.time.DurationFormatUtils;
 import org.apache.solr.client.solrj.SolrServerException;
 import org.marc4j.MarcException;
 import org.marc4j.MarcReader;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/dao/DefaultMarcPositionalControlField.java b/src/main/java/de/gwdg/metadataqa/marc/dao/DefaultMarcPositionalControlField.java
index 1b0c2b6d7..8fca0d09c 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/dao/DefaultMarcPositionalControlField.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/dao/DefaultMarcPositionalControlField.java
@@ -1,7 +1,6 @@
 package de.gwdg.metadataqa.marc.dao;
 
 import de.gwdg.metadataqa.marc.definition.ControlValue;
-import de.gwdg.metadataqa.marc.definition.controlpositions.LeaderPositions;
 import de.gwdg.metadataqa.marc.definition.structure.ControlFieldDefinition;
 import de.gwdg.metadataqa.marc.definition.structure.ControlfieldPositionDefinition;
 import de.gwdg.metadataqa.marc.definition.structure.DefaultControlFieldDefinition;
@@ -9,8 +8,6 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import static de.gwdg.metadataqa.marc.definition.controlpositions.LeaderPositions.getPositionList;
-
 public class DefaultMarcPositionalControlField extends MarcPositionalControlField {
   private static final Logger logger = Logger.getLogger(DefaultMarcPositionalControlField.class.getCanonicalName());
 
diff --git a/src/main/java/de/gwdg/metadataqa/marc/dao/Leader.java b/src/main/java/de/gwdg/metadataqa/marc/dao/Leader.java
index a313c2ffb..809442fec 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/dao/Leader.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/dao/Leader.java
@@ -180,6 +180,7 @@ public String resolve(String key) {
     return resolve(LeaderPositions.getByLabel(key));
   }
 
+  @Override
   public Map<ControlfieldPositionDefinition, String> getMap() {
     return valuesMap;
   }
@@ -277,6 +278,7 @@ public ControlValue getLengthOfTheImplementationDefinedPortion() {
     return lengthOfTheImplementationDefinedPortion;
   }
 
+  @Override
   public void setMarcRecord(BibliographicRecord marcRecord) {
     this.marcRecord = marcRecord;
     for (ControlValue value : valuesList)
@@ -296,6 +298,7 @@ public Map<String, List<String>> getKeyValuePairs() {
     return getKeyValuePairs(SolrFieldType.MARC);
   }
 
+  @Override
   public Map<String, List<String>> getKeyValuePairs(SolrFieldType type) {
     Map<String, List<String>> map = new LinkedHashMap<>();
     PositionalControlFieldKeyGenerator keyGenerator = new PositionalControlFieldKeyGenerator(
@@ -309,6 +312,7 @@ public Map<String, List<String>> getKeyValuePairs(SolrFieldType type) {
     return map;
   }
 
+  @Override
   public List<ValidationError> getInitializationErrors() {
     return initializationErrors;
   }
diff --git a/src/main/java/de/gwdg/metadataqa/marc/dao/record/BibliographicRecord.java b/src/main/java/de/gwdg/metadataqa/marc/dao/record/BibliographicRecord.java
index e494e169a..43806c351 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/dao/record/BibliographicRecord.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/dao/record/BibliographicRecord.java
@@ -9,19 +9,10 @@
 import de.gwdg.metadataqa.marc.analysis.ShelfReadyFieldsBooks;
 import de.gwdg.metadataqa.marc.analysis.ThompsonTraillFields;
 import de.gwdg.metadataqa.marc.cli.utils.IgnorableFields;
-import de.gwdg.metadataqa.marc.dao.Control001;
-import de.gwdg.metadataqa.marc.dao.Control003;
-import de.gwdg.metadataqa.marc.dao.Control005;
-import de.gwdg.metadataqa.marc.dao.Control006;
-import de.gwdg.metadataqa.marc.dao.Control007;
-import de.gwdg.metadataqa.marc.dao.Control008;
 import de.gwdg.metadataqa.marc.dao.DataField;
-import de.gwdg.metadataqa.marc.dao.Leader;
 import de.gwdg.metadataqa.marc.dao.MarcControlField;
-import de.gwdg.metadataqa.marc.dao.MarcPositionalControlField;
 import de.gwdg.metadataqa.marc.definition.MarcVersion;
 import de.gwdg.metadataqa.marc.definition.bibliographic.SchemaType;
-import de.gwdg.metadataqa.marc.definition.structure.ControlfieldPositionDefinition;
 import de.gwdg.metadataqa.marc.definition.structure.DataFieldDefinition;
 import de.gwdg.metadataqa.marc.definition.structure.Indicator;
 import de.gwdg.metadataqa.marc.model.SolrFieldType;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/dao/record/Marc21Record.java b/src/main/java/de/gwdg/metadataqa/marc/dao/record/Marc21Record.java
index cfe3c6d9a..27e0b800d 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/dao/record/Marc21Record.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/dao/record/Marc21Record.java
@@ -2,7 +2,6 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import de.gwdg.metadataqa.marc.MarcFactory;
-import de.gwdg.metadataqa.marc.MarcSubfield;
 import de.gwdg.metadataqa.marc.analysis.AuthorityCategory;
 import de.gwdg.metadataqa.marc.analysis.ShelfReadyFieldsBooks;
 import de.gwdg.metadataqa.marc.analysis.ThompsonTraillFields;
@@ -56,6 +55,7 @@ public Marc21Record() {
     super();
   }
 
+  @Override
   public String getId() {
     if (id != null)
       return id;
@@ -188,6 +188,7 @@ public void setControl008(MarcPositionalControlField control008) {
     controlfieldIndex.put(control008.getDefinition().getTag(), Arrays.asList(control008));
   }
 
+  @Override
   public Map<String, List<String>> getKeyValuePairs(SolrFieldType type,
                                                     boolean withDeduplication,
                                                     MarcVersion marcVersion) {
@@ -209,6 +210,7 @@ public Map<String, List<String>> getKeyValuePairs(SolrFieldType type,
     return mainKeyValuePairs;
   }
 
+  @Override
   public String asJson() {
     ObjectMapper mapper = new ObjectMapper();
 
@@ -224,6 +226,7 @@ public String asJson() {
     return transformMapToJson(mapper, map);
   }
 
+  @Override
   public List<String> search(String path, String query) {
     List<String> results = new ArrayList<>();
     if (path.equals("001") || path.equals("003") || path.equals("005")) {
@@ -315,6 +318,7 @@ private void searchByPosition(String query, List<String> results, Matcher matche
     }
   }
 
+  @Override
   public List<String> select(MarcSpec selector) {
     List<String> results = new ArrayList<>();
     if (selector.getFieldTag().equals("LDR") && leader != null && StringUtils.isNotEmpty(leader.getContent())) {
@@ -390,6 +394,7 @@ public Map<ThompsonTraillFields, List<String>> getThompsonTraillTagsMap() {
     return null;
   }
 
+  @Override
   public void setField(String tag, String content, MarcVersion marcVersion) {
     if (marcVersion.equals(MarcVersion.UNIMARC)) {
       content = UnimarcConverter.contentFromUnimarc(tag, content);
@@ -419,6 +424,7 @@ public void setField(String tag, String content, MarcVersion marcVersion) {
     }
   }
 
+  @Override
   public void setField(String tag, String ind1, String ind2, String content, MarcVersion marcVersion) {
 
     if (tag.equals("001")) {
diff --git a/src/main/java/de/gwdg/metadataqa/marc/dao/record/PicaRecord.java b/src/main/java/de/gwdg/metadataqa/marc/dao/record/PicaRecord.java
index 6ab5fce7e..10a30b2f9 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/dao/record/PicaRecord.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/dao/record/PicaRecord.java
@@ -5,7 +5,6 @@
 import de.gwdg.metadataqa.marc.analysis.ShelfReadyFieldsBooks;
 import de.gwdg.metadataqa.marc.analysis.ThompsonTraillFields;
 import de.gwdg.metadataqa.marc.dao.DataField;
-import de.gwdg.metadataqa.marc.dao.MarcPositionalControlField;
 import de.gwdg.metadataqa.marc.definition.bibliographic.SchemaType;
 import de.gwdg.metadataqa.marc.utils.pica.PicaSubjectManager;
 import de.gwdg.metadataqa.marc.utils.pica.crosswalk.Crosswalk;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags3xx/Tag353.java b/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags3xx/Tag353.java
index ef84f579c..1a2bdf198 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags3xx/Tag353.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags3xx/Tag353.java
@@ -11,11 +11,8 @@
 
 import java.util.Arrays;
 
-import static de.gwdg.metadataqa.marc.definition.FRBRFunction.DiscoveryIdentify;
 import static de.gwdg.metadataqa.marc.definition.FRBRFunction.ManagementIdentify;
 import static de.gwdg.metadataqa.marc.definition.FRBRFunction.ManagementProcess;
-import static de.gwdg.metadataqa.marc.definition.FRBRFunction.UseInterpret;
-import static de.gwdg.metadataqa.marc.definition.FRBRFunction.UseOperate;
 
 /**
  * Supplementary Content Characteristics
diff --git a/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags84x/Tag857.java b/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags84x/Tag857.java
index 4df25fe61..dd77bdb84 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags84x/Tag857.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/definition/tags/tags84x/Tag857.java
@@ -3,7 +3,6 @@
 import de.gwdg.metadataqa.marc.definition.Cardinality;
 import de.gwdg.metadataqa.marc.definition.MarcVersion;
 import de.gwdg.metadataqa.marc.definition.general.codelist.ElectronicAccessMethodsCodeList;
-import de.gwdg.metadataqa.marc.definition.general.codelist.OrganizationCodes;
 import de.gwdg.metadataqa.marc.definition.general.parser.LinkageParser;
 import de.gwdg.metadataqa.marc.definition.structure.DataFieldDefinition;
 import de.gwdg.metadataqa.marc.definition.structure.Indicator;
@@ -14,8 +13,6 @@
 import static de.gwdg.metadataqa.marc.definition.FRBRFunction.DiscoveryIdentify;
 import static de.gwdg.metadataqa.marc.definition.FRBRFunction.DiscoveryObtain;
 import static de.gwdg.metadataqa.marc.definition.FRBRFunction.DiscoverySelect;
-import static de.gwdg.metadataqa.marc.definition.FRBRFunction.ManagementIdentify;
-import static de.gwdg.metadataqa.marc.definition.FRBRFunction.ManagementProcess;
 
 /**
  * Electronic Archive Location and Access
diff --git a/src/main/java/de/gwdg/metadataqa/marc/utils/marcspec/legacy/MarcSpec.java b/src/main/java/de/gwdg/metadataqa/marc/utils/marcspec/legacy/MarcSpec.java
index 1b90c63d0..bd833b7d1 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/utils/marcspec/legacy/MarcSpec.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/utils/marcspec/legacy/MarcSpec.java
@@ -16,7 +16,7 @@
  */
 public class MarcSpec implements SchemaSpec, Serializable {
 
-  private static final Pattern fieldTagPattern = Pattern.compile("[X0-9]{3,3}|LDR");
+  private static final Pattern fieldTagPattern = Pattern.compile("[X0-9]{3}|LDR");
   private static final Pattern hasSpacePattern = Pattern.compile("\\s");
   private static final Pattern indicatorPattern = Pattern.compile("[a-z0-9_]");
   private static final Pattern subfieldsPattern = Pattern.compile("[a-z0-9!\\\"#$%&'()*+-./:;<=>?]");
diff --git a/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaFieldDefinition.java b/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaFieldDefinition.java
index 5299a1a08..b9f65fbbf 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaFieldDefinition.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaFieldDefinition.java
@@ -12,7 +12,7 @@ public class PicaFieldDefinition extends DataFieldDefinition {
   private String id;
   private String counter;
 
-  private PicaFieldDefinition(){};
+  private PicaFieldDefinition() {}
 
   public PicaFieldDefinition(PicaTagDefinition picaTagDefinition) {
     tag = picaTagDefinition.getTag();
@@ -55,11 +55,9 @@ public String getId() {
 
   public boolean inRange(String occurrence) {
     if (range != null && range.getUnitLength() == occurrence.length())
-      if (range.isHasRange()) {
-        if (range.getStart().compareTo(occurrence) > 0 || range.getEnd().compareTo(occurrence) < 0)
-          return false;
-        return true;
-      } else
+      if (range.isHasRange())
+        return range.getStart().compareTo(occurrence) <= 0 && range.getEnd().compareTo(occurrence) >= 0;
+      else
         return range.getStart().equals(occurrence);
 
     return false;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaRange.java b/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaRange.java
index 8970bfa10..5524fc20b 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaRange.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaRange.java
@@ -1,6 +1,9 @@
 package de.gwdg.metadataqa.marc.utils.pica;
 
-public class PicaRange {
+import java.io.Serializable;
+
+public class PicaRange implements Serializable {
+  private static final long serialVersionUID = -6398191971175762735L;
   private String raw;
   private String start;
   private String end;
diff --git a/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaVocabularyManager.java b/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaVocabularyManager.java
index 1f24b98f6..779d2ac0d 100644
--- a/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaVocabularyManager.java
+++ b/src/main/java/de/gwdg/metadataqa/marc/utils/pica/PicaVocabularyManager.java
@@ -10,7 +10,6 @@
 import java.io.FileReader;
 import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.io.UnsupportedEncodingException;
 import java.nio.charset.StandardCharsets;
 import java.util.Collection;
 import java.util.HashMap;