diff --git a/java/org/slub/rosetta/dps/repository/plugin/SLUBTechnicalMetadataExtractorCheckItTiffPlugin.java b/java/org/slub/rosetta/dps/repository/plugin/SLUBTechnicalMetadataExtractorCheckItTiffPlugin.java
index 4075ccbf4919dc3ba8764e3081684439f212e688..e01fb281ba58c928f2d87ff6867d435d99f6a59d 100644
--- a/java/org/slub/rosetta/dps/repository/plugin/SLUBTechnicalMetadataExtractorCheckItTiffPlugin.java
+++ b/java/org/slub/rosetta/dps/repository/plugin/SLUBTechnicalMetadataExtractorCheckItTiffPlugin.java
@@ -50,19 +50,19 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
     private enum Checkit_tiff_versions {
         current, upcoming
     }
-    private final Map<Checkit_tiff_versions, String> checkit_tiff_binary_path = new HashMap<Checkit_tiff_versions, String>();
-    private final Map<Checkit_tiff_versions, String> checkit_tiff_config_path = new HashMap<Checkit_tiff_versions, String>();
-    private String exiftool_binary_path;
-    private List<String> extractionErrors = new ArrayList<String>();
-    private final List<String> validationLog = new ArrayList<String>();
+    private final Map<Checkit_tiff_versions, String> checkit_tiff_binary_path = new HashMap<>();
+    private final Map<Checkit_tiff_versions, String> checkit_tiff_config_path = new HashMap<>();
+    private String exiftool_binary_path = null;
+    private List<String> extractionErrors = new ArrayList<>();
+    private final List<String> validationLog = new ArrayList<>();
     private Boolean isvalid = false;
     private Boolean iswellformed = false;
-    private final Map<String,String> attributes = new HashMap<String, String>();
-    private Map<Checkit_tiff_versions, String> md5Profile = new HashMap<>();
-    private Map<Checkit_tiff_versions, String> md5CheckitTiff = new HashMap<>();
+    private final Map<String,String> attributes = new HashMap<>();
+    private final Map<Checkit_tiff_versions, String> md5Profile = new HashMap<>();
+    private final Map<Checkit_tiff_versions, String> md5CheckitTiff = new HashMap<>();
     private boolean isDifferentProfile = true;
-    private boolean isDifferentCheckItTiff = true;
-    private Map<Checkit_tiff_versions, Boolean> is_checkit_tiff_valid = new HashMap<Checkit_tiff_versions, Boolean>();
+    private final boolean isDifferentCheckItTiff = true;
+    private final Map<Checkit_tiff_versions, Boolean> is_checkit_tiff_valid = new HashMap<>();
 
 
     /** constructor */
@@ -76,7 +76,7 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
     /** init params to configure the plugin via xml forms
      * @param initp parameter map
      */
-    public void initParams(Map<String, String> initp) {
+    public final void initParams(Map<String, String> initp) {
         this.checkit_tiff_binary_path.put(Checkit_tiff_versions.current, initp.get("current_checkit_tiff").trim());
         this.checkit_tiff_binary_path.put(Checkit_tiff_versions.upcoming, initp.get("upcoming_checkit_tiff").trim());
         this.checkit_tiff_config_path.put(Checkit_tiff_versions.current, initp.get("current_config_file").trim());
@@ -134,7 +134,7 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
     }
 
     @Override
-    public void extract(String filePath) throws Exception {
+    public final void extract(String filePath) throws Exception {
         validate_tiff_by_upcoming_checkit_tiff(filePath);
         /* only check against current checkit_tiff if upcoming fails */
         if ((this.isDifferentCheckItTiff || isDifferentProfile) && is_checkit_tiff_valid.get(Checkit_tiff_versions.upcoming) == false) {
@@ -164,14 +164,14 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
             p.waitFor();
             BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
             String line=reader.readLine();
-            String response="";
+            StringBuilder response= new StringBuilder();
             while (line != null) {
                 log.debug(line);
                 parse_exiftool_output(line.trim());
-                response+=line;
+                response.append(line);
                 line = reader.readLine();
             }
-            attributes.put("exiftool-log", response.trim());
+            attributes.put("exiftool-log", response.toString().trim());
 
         } catch (IOException e) {
             log.error(e);
@@ -218,7 +218,7 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
         validate_tiff_by_checkit_tiff_version(filePath, Checkit_tiff_versions.upcoming);
     }
 
-    public String getAgentName() {
+    public final String getAgentName() {
         log.debug("getAgentName() called");
         return "checkit_tiff";
     }
@@ -227,11 +227,11 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
      *
      * @return string with version
      */
-    public String getAgent() {
+    public final String getAgent() {
         log.debug("getAgent() called");
-        String response="";
+        StringBuilder response= new StringBuilder();
         for (Checkit_tiff_versions version : Checkit_tiff_versions.values()) {
-            response += (version.name() + " checkit_tiff:\n");
+            response.append(version.name()).append(" checkit_tiff:\n");
             try {
                 String execstring = this.checkit_tiff_binary_path.get(version) + " -v";
                 Process p = Runtime.getRuntime().exec(execstring);
@@ -240,7 +240,7 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
                 String line = reader.readLine();
                 while (line != null) {
                     log.debug(line);
-                    response += line;
+                    response.append(line);
                     line = reader.readLine();
                 }
             } catch (IOException e) {
@@ -250,11 +250,11 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
                 e.printStackTrace();
             }
         }
-        return response.trim();
+        return response.toString().trim();
     }
 
     @Override
-    public String getAttributeByName(String attribute) {
+    public final String getAttributeByName(String attribute) {
       if (attributes.containsKey(attribute)) {
           return attributes.get(attribute);
       }
@@ -262,7 +262,7 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
     }
 
     @Override
-    public List<String> getExtractionErrors() {
+    public final List<String> getExtractionErrors() {
       return this.extractionErrors;
     }
     /* processed using:
@@ -278,9 +278,9 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
      *
      * */
     @Override
-    public List<String> getSupportedAttributeNames() {
+    public final List<String> getSupportedAttributeNames() {
       //return new ArrayList<String>(attributes.keySet());
-        List<String> available = new ArrayList<String>();
+        List<String> available = new ArrayList<>();
         //available.add("checkit-tiff-conf");
         available.add("checkit-tiff-log");
         //available.add("checkit-tiff-path");
@@ -1092,47 +1092,44 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
     }
 
     @Override
-    public boolean isWellFormed() {
+    public final boolean isWellFormed() {
       return this.iswellformed;
     }
 
     @Override
-    public boolean isValid() {
+    public final boolean isValid() {
         log.debug("is valid=" + this.isvalid);
         return this.isvalid;
     }
     @Override
-    public String getFormatName() {
+    public final String getFormatName() {
         return "TIFF";
     }
 
     @Override
-    public String getFormatVersion() {
+    public final String getFormatVersion() {
       return "6 (baseline + SLUB extensions)";
     }
 
     @Override
-    public Integer getImageCount() {
+    public final Integer getImageCount() {
         return 1; //baseline tiff holds exact one
     }
 
     @Override
-    public String getMimeType() {
+    public final String getMimeType() {
       return "image/tiff";
     }
 
     @Override
-    public String getProfile () {
+    public final String getProfile() {
         /* there is no documentation in ExL API, therefore we use it to document the profile versions in a light way */
-        String returnvalue = "";
+        StringBuilder returnvalue = new StringBuilder();
         for (Checkit_tiff_versions v: Checkit_tiff_versions.values()) {
             String modificationdate = modificationDateOfFile(this.checkit_tiff_config_path.get(v));
-            returnvalue = returnvalue + v + "profile:\n"
-                    + "  path=" + this.checkit_tiff_config_path.get(v) + "\n"
-                    + "  md5sum=" + this.md5CheckitTiff.get(v) + "\n"
-                    + "  modification date=" + modificationdate + "\n";
+            returnvalue.append(v).append("profile:\n").append("  path=").append(this.checkit_tiff_config_path.get(v)).append("\n").append("  md5sum=").append(this.md5CheckitTiff.get(v)).append("\n").append("  modification date=").append(modificationdate).append("\n");
         }
-        return returnvalue;
+        return returnvalue.toString();
     }
 
     private String md5SumOfFile(String filename ) {
@@ -1140,8 +1137,7 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
             MessageDigest md = MessageDigest.getInstance("MD5");
             byte[] b = Files.readAllBytes(Paths.get(filename));
             byte[] digest = md.digest(b);
-            String hexdigest = new BigInteger(1, digest).toString(16);
-            return hexdigest;
+            return new BigInteger(1, digest).toString(16);
         } catch (Exception e) {
             e.printStackTrace();
         }
@@ -1157,15 +1153,13 @@ public class SLUBTechnicalMetadataExtractorCheckItTiffPlugin implements MDExtrac
         return "";
     }
 
-    /** stand-alone check, main file to call local installed clamd
-     * @param args list of files which should be scanned
-     */
-    /** stand-alone check, main file to call local installed clamd
+
+    /** stand-alone check, main file
      * @param args list of files which should be scanned
      */
     public static void main(String[] args) {
         SLUBTechnicalMetadataExtractorCheckItTiffPlugin plugin = new SLUBTechnicalMetadataExtractorCheckItTiffPlugin();
-        Map<String, String> initp = new HashMap<String, String>();
+        Map<String, String> initp = new HashMap<>();
         initp.put( "current_checkit_tiff", "/operational_shared/software/checkit_tiff_current");
         initp.put( "current_config_file", "/operational_shared/software/cit_tiff6_baseline_SLUB_current.cfg");
         initp.put( "upcoming_checkit_tiff", "/operational_shared/software/checkit_tiff_upcoming");