diff --git a/dspace-api/src/main/java/org/dspace/app/bulkedit/DSpaceCSVLine.java b/dspace-api/src/main/java/org/dspace/app/bulkedit/DSpaceCSVLine.java
index ca40007881..2f2cf09ebf 100644
--- a/dspace-api/src/main/java/org/dspace/app/bulkedit/DSpaceCSVLine.java
+++ b/dspace-api/src/main/java/org/dspace/app/bulkedit/DSpaceCSVLine.java
@@ -39,10 +39,11 @@
 package org.dspace.app.bulkedit;
 
 import java.util.ArrayList;
-import java.util.Hashtable;
-import java.util.Enumeration;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 /**
  * Utility class to store a line from a CSV file
@@ -55,7 +56,7 @@ public class DSpaceCSVLine
     private int id;
 
     /** The elements in this line in a hashtable, keyed by the metadata type */
-    private Hashtable<String, ArrayList> items;
+    private Map<String, ArrayList> items;
 
     /**
      * Create a new CSV line
@@ -66,7 +67,7 @@ public class DSpaceCSVLine
     {
         // Store the ID + separator, and initialise the hashtable
         this.id = id;
-        items = new Hashtable<String, ArrayList>();
+        items = new HashMap<String, ArrayList>();
     }
 
     /**
@@ -76,7 +77,7 @@ public class DSpaceCSVLine
     {
         // Set the ID to be -1, and initialise the hashtable
         this.id = -1;
-        this.items = new Hashtable<String, ArrayList>();
+        this.items = new HashMap<String, ArrayList>();
     }
 
     /**
@@ -128,10 +129,10 @@ public class DSpaceCSVLine
      *
      * @return An enumeration of all the keys
      */
-    public Enumeration<String> keys()
+    public Set<String> keys()
     {
         // Return the keys
-        return items.keys();
+        return items.keySet();
     }
 
     /**
diff --git a/dspace-api/src/main/java/org/dspace/app/bulkedit/MetadataImport.java b/dspace-api/src/main/java/org/dspace/app/bulkedit/MetadataImport.java
index cd9a22dbe7..48feb56425 100644
--- a/dspace-api/src/main/java/org/dspace/app/bulkedit/MetadataImport.java
+++ b/dspace-api/src/main/java/org/dspace/app/bulkedit/MetadataImport.java
@@ -48,7 +48,6 @@ import org.dspace.eperson.EPerson;
 import org.dspace.workflow.WorkflowManager;
 
 import java.util.ArrayList;
-import java.util.Enumeration;
 import java.io.File;
 import java.io.InputStreamReader;
 import java.io.BufferedReader;
@@ -137,11 +136,9 @@ public class MetadataImport
                     }
 
                     // Iterate through each metadata element in the csv line
-                    Enumeration<String> e = line.keys();
-                    while (e.hasMoreElements())
+                    for (String md : line.keys())
                     {
                         // Get the values we already have
-                        String md = e.nextElement();
                         if (!"id".equals(md))
                         {
                             // Get the values from the CSV
@@ -169,12 +166,10 @@ public class MetadataImport
                     }
 
                     // Iterate through each metadata element in the csv line
-                    Enumeration<String> e = line.keys();
                     BulkEditChange whatHasChanged = new BulkEditChange();
-                    while (e.hasMoreElements())
+                    for (String md : line.keys())
                     {
                         // Get the values we already have
-                        String md = e.nextElement();
                         if (!"id".equals(md))
                         {
                             // Get the values from the CSV
diff --git a/dspace-api/src/main/java/org/dspace/app/statistics/HTMLReport.java b/dspace-api/src/main/java/org/dspace/app/statistics/HTMLReport.java
index 1c1dfae4f8..735f056d7e 100644
--- a/dspace-api/src/main/java/org/dspace/app/statistics/HTMLReport.java
+++ b/dspace-api/src/main/java/org/dspace/app/statistics/HTMLReport.java
@@ -210,7 +210,7 @@ public class HTMLReport implements Report
      */
     public void setStartDate(Date start)
     {
-        this.start = start;
+        this.start = start == null ? null : (Date)start.clone();
     }
     
     
@@ -221,7 +221,7 @@ public class HTMLReport implements Report
      */
     public void setEndDate(Date end)
     {
-        this.end = end;
+        this.end = end == null ? null : (Date)end.clone();
     }
     
     
diff --git a/dspace-api/src/main/java/org/dspace/checker/BitstreamInfo.java b/dspace-api/src/main/java/org/dspace/checker/BitstreamInfo.java
index 628cdb6061..ac047e8c03 100644
--- a/dspace-api/src/main/java/org/dspace/checker/BitstreamInfo.java
+++ b/dspace-api/src/main/java/org/dspace/checker/BitstreamInfo.java
@@ -148,9 +148,9 @@ public final class BitstreamInfo
                 nm, "");
 
         this.deleted = del;
-        this.processEndDate = procEndDate;
+        this.processEndDate = processEndDate == null ? null : (Date)procEndDate.clone();
         this.toBeProcessed = toBeProc;
-        this.processStartDate = procStartDate;
+        this.processStartDate = processStartDate == null ? null : (Date)procStartDate.clone();
         this.infoFound = true;
     }
 
@@ -529,7 +529,7 @@ public final class BitstreamInfo
      */
     public Date getProcessStartDate()
     {
-        return this.processStartDate;
+        return this.processStartDate == null ? null : (Date)this.processStartDate.clone();
     }
 
     /**
@@ -540,7 +540,7 @@ public final class BitstreamInfo
      */
     public void setProcessStartDate(Date startDate)
     {
-        this.processStartDate = startDate;
+        this.processStartDate = startDate == null ? null : (Date)startDate.clone();
     }
 
     /**
@@ -550,7 +550,7 @@ public final class BitstreamInfo
      */
     public Date getProcessEndDate()
     {
-        return this.processEndDate;
+        return this.processEndDate == null ? null : (Date)this.processEndDate.clone();
     }
 
     /**
@@ -561,6 +561,6 @@ public final class BitstreamInfo
      */
     public void setProcessEndDate(Date endDate)
     {
-        this.processEndDate = endDate;
+        this.processEndDate = endDate == null ? null : (Date)endDate.clone();
     }
 }
diff --git a/dspace-api/src/main/java/org/dspace/checker/CheckerCommand.java b/dspace-api/src/main/java/org/dspace/checker/CheckerCommand.java
index 927a440d97..d228ef6c8f 100644
--- a/dspace-api/src/main/java/org/dspace/checker/CheckerCommand.java
+++ b/dspace-api/src/main/java/org/dspace/checker/CheckerCommand.java
@@ -423,7 +423,7 @@ public final class CheckerCommand
      */
     public Date getProcessStartDate()
     {
-        return processStartDate;
+        return processStartDate == null ? null : (Date)processStartDate.clone();
     }
 
     /**
@@ -434,7 +434,7 @@ public final class CheckerCommand
      */
     public void setProcessStartDate(Date startDate)
     {
-        processStartDate = startDate;
+        processStartDate = startDate == null ? null : (Date)startDate.clone();
     }
 
     /**
diff --git a/dspace-api/src/main/java/org/dspace/checker/ChecksumHistory.java b/dspace-api/src/main/java/org/dspace/checker/ChecksumHistory.java
index 3591ee0ff0..4f8ca3d30e 100644
--- a/dspace-api/src/main/java/org/dspace/checker/ChecksumHistory.java
+++ b/dspace-api/src/main/java/org/dspace/checker/ChecksumHistory.java
@@ -99,8 +99,8 @@ public class ChecksumHistory
             String checksumExpted, String checksumCalc, String inResult)
     {
         this.bitstreamId = bitstrmId;
-        this.processStartDate = startDate;
-        this.processEndDate = endDate;
+        this.processStartDate = startDate == null ? null : (Date)startDate.clone();
+        this.processEndDate = endDate == null ? null : (Date)endDate.clone();
         this.checksumExpected = checksumExpted;
         this.checksumCalculated = checksumCalc;
         this.result = inResult;
@@ -161,7 +161,7 @@ public class ChecksumHistory
      */
     public Date getProcessEndDate()
     {
-        return processEndDate;
+        return processEndDate == null ? null : (Date)processEndDate.clone();
     }
 
     /**
@@ -172,7 +172,7 @@ public class ChecksumHistory
      */
     public void setProcessEndDate(Date processEndDate)
     {
-        this.processEndDate = processEndDate;
+        this.processEndDate = processEndDate == null ? null : (Date)processEndDate.clone();
     }
 
     /**
@@ -183,7 +183,7 @@ public class ChecksumHistory
      */
     public Date getProcessStartDate()
     {
-        return processStartDate;
+        return processStartDate == null ? null : (Date)processStartDate.clone();
     }
 
     /**
@@ -195,7 +195,7 @@ public class ChecksumHistory
      */
     public void setProcessStartDate(Date processStartDate)
     {
-        this.processStartDate = processStartDate;
+        this.processStartDate = processStartDate == null ? null : (Date)processStartDate.clone();
     }
 
     /**
diff --git a/dspace-api/src/main/java/org/dspace/checker/SimpleDispatcher.java b/dspace-api/src/main/java/org/dspace/checker/SimpleDispatcher.java
index e716f2ef7f..7128e3efb1 100644
--- a/dspace-api/src/main/java/org/dspace/checker/SimpleDispatcher.java
+++ b/dspace-api/src/main/java/org/dspace/checker/SimpleDispatcher.java
@@ -69,11 +69,10 @@ public class SimpleDispatcher implements BitstreamDispatcher
      *            indicates whether checker should loop infinitely through
      *            most_recent_checksum table
      */
-    public SimpleDispatcher(BitstreamInfoDAO bitstreamInfoDAO, Date startTime,
-            boolean looping)
+    public SimpleDispatcher(BitstreamInfoDAO bitstreamInfoDAO, Date startTime, boolean looping)
     {
         this.bitstreamInfoDAO = bitstreamInfoDAO;
-        this.processStartTime = startTime;
+        this.processStartTime = startTime == null ? null : (Date)startTime.clone();
         this.loopContinuously = looping;
     }
 
diff --git a/dspace-api/src/main/java/org/dspace/core/Context.java b/dspace-api/src/main/java/org/dspace/core/Context.java
index ca538a9cfb..5726453f21 100644
--- a/dspace-api/src/main/java/org/dspace/core/Context.java
+++ b/dspace-api/src/main/java/org/dspace/core/Context.java
@@ -610,5 +610,14 @@ public class Context
         {
             abort();
         }
+
+        try
+        {
+            super.finalize();
+        }
+        catch (Throwable t)
+        {
+            log.error("Unable to finalize object", t);
+        }
     }
 }
diff --git a/dspace-api/src/main/java/org/dspace/storage/rdbms/TableRowIterator.java b/dspace-api/src/main/java/org/dspace/storage/rdbms/TableRowIterator.java
index 7b86efac6c..6ce3ba399d 100644
--- a/dspace-api/src/main/java/org/dspace/storage/rdbms/TableRowIterator.java
+++ b/dspace-api/src/main/java/org/dspace/storage/rdbms/TableRowIterator.java
@@ -39,6 +39,8 @@
  */
 package org.dspace.storage.rdbms;
 
+import org.apache.log4j.Logger;
+
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
@@ -53,6 +55,7 @@ import java.util.List;
  */
 public class TableRowIterator
 {
+    private final static Logger log = Logger.getLogger(TableRowIterator.class);
     /**
      * Results from a query
      */
@@ -111,6 +114,15 @@ public class TableRowIterator
     protected void finalize()
     {
         close();
+
+        try
+        {
+            super.finalize();
+        }
+        catch (Throwable t)
+        {
+            log.error("Unable to finalize object", t);
+        }
     }
 
     /**
diff --git a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/ControlledVocabularyTag.java b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/ControlledVocabularyTag.java
index 81d6b6a0f3..dfb6ba382d 100644
--- a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/ControlledVocabularyTag.java
+++ b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/ControlledVocabularyTag.java
@@ -35,9 +35,9 @@ package org.dspace.app.webui.jsptag;
 
 import java.io.File;
 import java.io.FilenameFilter;
-import java.util.Enumeration;
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.Iterator;
+import java.util.Map;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.jsp.JspException;
@@ -73,7 +73,7 @@ public class ControlledVocabularyTag extends TagSupport
     private String vocabulary;
 
     // an hashtable containing all the loaded vocabularies
-    public Hashtable controlledVocabularies;
+    public Map<String, Document> controlledVocabularies;
 
     /**
      * Process tag
@@ -95,27 +95,23 @@ public class ControlledVocabularyTag extends TagSupport
                 + "vocabulary2html.xsl";
 
         // Load vocabularies on startup
-        controlledVocabularies = (Hashtable) pageContext.getServletContext()
-                .getAttribute("controlledvocabulary.controlledVocabularies");
+        controlledVocabularies = (Map<String, Document>) pageContext.getServletContext().getAttribute("controlledvocabulary.controlledVocabularies");
         if (controlledVocabularies == null)
         {
             controlledVocabularies = loadControlledVocabularies(vocabulariesPath);
-            pageContext.getServletContext().setAttribute(
-                    "controlledvocabulary.controlledVocabularies",
-                    controlledVocabularies);
+            pageContext.getServletContext().setAttribute("controlledvocabulary.controlledVocabularies", controlledVocabularies);
         }
 
         try
         {
-            Hashtable prunnedVocabularies = needsFiltering() ? filterVocabularies(
-                    controlledVocabularies, vocabularyPrunningXSLT)
+            Map<String, Document> prunnedVocabularies = needsFiltering() ?
+                    filterVocabularies(controlledVocabularies, vocabularyPrunningXSLT)
                     : controlledVocabularies;
 
             String html = "";
             if (vocabulary != null && !vocabulary.equals(""))
             {
-                html = renderVocabularyAsHTML((Document) prunnedVocabularies
-                        .get(vocabulary + ".xml"),
+                html = renderVocabularyAsHTML(prunnedVocabularies.get(vocabulary + ".xml"),
                         controlledVocabulary2HtmlXSLT,
                         isAllowMultipleSelection(), request.getContextPath());
             }
@@ -171,14 +167,14 @@ public class ControlledVocabularyTag extends TagSupport
      *            The context path
      * @return the HTML that represents the vocabularies
      */
-    private String renderVocabulariesAsHTML(Hashtable vocabularies,
+    private String renderVocabulariesAsHTML(Map<String, Document> vocabularies,
             String xslt, boolean allowMultipleSelection, String contextPath)
     {
         StringBuilder result = new StringBuilder();
-        Iterator iter = vocabularies.values().iterator();
+        Iterator<Document> iter = vocabularies.values().iterator();
         while (iter.hasNext())
         {
-            Document controlledVocabularyXML = (Document) iter.next();
+            Document controlledVocabularyXML = iter.next();
             result.append(renderVocabularyAsHTML(controlledVocabularyXML, xslt,
                     allowMultipleSelection, contextPath));
         }
@@ -196,18 +192,12 @@ public class ControlledVocabularyTag extends TagSupport
      *            the filename of the stylesheet that trimms the taxonomies
      * @return An hashtable with all the filtered vocabularies
      */
-    private Hashtable filterVocabularies(Hashtable vocabularies,
-            String vocabularyPrunningXSLT)
+    private Map<String, Document> filterVocabularies(Map<String, Document> vocabularies, String vocabularyPrunningXSLT)
     {
-        Hashtable prunnedVocabularies = new Hashtable();
-        Enumeration enumeration = vocabularies.keys();
-        while (enumeration.hasMoreElements())
+        Map<String, Document> prunnedVocabularies = new HashMap<String, Document>();
+        for (Map.Entry<String, Document> entry : vocabularies.entrySet())
         {
-            String controlledVocabularyKey = (String) enumeration.nextElement();
-            Document controlledVocabulary = (Document) vocabularies
-                    .get(controlledVocabularyKey);
-            prunnedVocabularies.put(controlledVocabularyKey, filterVocabulary(
-                    controlledVocabulary, vocabularyPrunningXSLT, getFilter()));
+            prunnedVocabularies.put(entry.getKey(), filterVocabulary(entry.getValue(), vocabularyPrunningXSLT, getFilter()));
         }
         return prunnedVocabularies;
     }
@@ -239,12 +229,10 @@ public class ControlledVocabularyTag extends TagSupport
         try
         {
 
-            Hashtable parameters = new Hashtable();
-            parameters.put("allowMultipleSelection",
-                    allowMultipleSelection ? "yes" : "no");
+            Map<String, String> parameters = new HashMap<String, String>();
+            parameters.put("allowMultipleSelection", allowMultipleSelection ? "yes" : "no");
             parameters.put("contextPath", contextPath);
-            result = XMLUtil.transformDocumentAsString(vocabulary, parameters,
-                    controlledVocabulary2HtmlXSLT);
+            result = XMLUtil.transformDocumentAsString(vocabulary, parameters, controlledVocabulary2HtmlXSLT);
         }
         catch (Exception e)
         {
@@ -265,8 +253,7 @@ public class ControlledVocabularyTag extends TagSupport
      *            The filter to be applied
      * @return The trimmed vocabulary.
      */
-    public Document filterVocabulary(Document vocabulary,
-            String vocabularyPrunningXSLT, String filter)
+    public Document filterVocabulary(Document vocabulary, String vocabularyPrunningXSLT, String filter)
     {
         if (vocabulary == null)
         {
@@ -275,10 +262,9 @@ public class ControlledVocabularyTag extends TagSupport
 
         try
         {
-            Hashtable parameters = new Hashtable();
+            Map<String, String> parameters = new HashMap<String, String>();
             parameters.put("filter", filter);
-            Document prunnedVocabulary = XMLUtil.transformDocument(vocabulary,
-                    parameters, vocabularyPrunningXSLT);
+            Document prunnedVocabulary = XMLUtil.transformDocument(vocabulary, parameters, vocabularyPrunningXSLT);
             return prunnedVocabulary;
         }
         catch (Exception e)
@@ -298,9 +284,9 @@ public class ControlledVocabularyTag extends TagSupport
      * @return an hashtable with the filenames of the vocabularies as keys and
      *         the XML documents representing the vocabularies as values.
      */
-    private static Hashtable loadControlledVocabularies(String directory)
+    private static Map<String, Document> loadControlledVocabularies(String directory)
     {
-        Hashtable controlledVocabularies = new Hashtable();
+        Map<String, Document> controlledVocabularies = new HashMap<String, Document>();
         File dir = new File(directory);
 
         FilenameFilter filter = new FilenameFilter()
@@ -320,8 +306,7 @@ public class ControlledVocabularyTag extends TagSupport
 
                 try
                 {
-                    Document controlledVocabulary = XMLUtil.loadXML(directory
-                            + filename);
+                    Document controlledVocabulary = XMLUtil.loadXML(directory + filename);
                     controlledVocabularies.put(filename, controlledVocabulary);
                     log.warn("Loaded vocabulary: " + filename);
                 }
diff --git a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectEPersonTag.java b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectEPersonTag.java
index 0a7902298c..4f64853c75 100644
--- a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectEPersonTag.java
+++ b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectEPersonTag.java
@@ -47,6 +47,7 @@ import javax.servlet.jsp.JspWriter;
 import javax.servlet.jsp.jstl.fmt.LocaleSupport;
 import javax.servlet.jsp.tagext.TagSupport;
 
+import org.apache.commons.lang.ArrayUtils;
 import org.dspace.eperson.EPerson;
 
 /**
@@ -119,7 +120,7 @@ public class SelectEPersonTag extends TagSupport
         }
         else if (e instanceof EPerson[])
         {
-            epeople = (EPerson[]) e;
+            epeople = (EPerson[])ArrayUtils.clone((EPerson[])e);
         }
     }
 
diff --git a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectGroupTag.java b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectGroupTag.java
index 90b000b821..3990c87b09 100644
--- a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectGroupTag.java
+++ b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/jsptag/SelectGroupTag.java
@@ -48,6 +48,7 @@ import javax.servlet.jsp.JspWriter;
 import javax.servlet.jsp.jstl.fmt.LocaleSupport;
 import javax.servlet.jsp.tagext.TagSupport;
 
+import org.apache.commons.lang.ArrayUtils;
 import org.dspace.eperson.Group;
 
 /**
@@ -114,7 +115,7 @@ public class SelectGroupTag extends TagSupport
 		}
 		else if(g instanceof Group[])
 		{
-			groups = (Group[]) g;
+			groups = (Group[])ArrayUtils.clone((Group[]) g);
 		}
 	}
 
diff --git a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/EditProfileServlet.java b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/EditProfileServlet.java
index ff4ca1ea46..98ab058754 100644
--- a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/EditProfileServlet.java
+++ b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/EditProfileServlet.java
@@ -88,7 +88,7 @@ public class EditProfileServlet extends DSpaceServlet
         // Find out if they're trying to set a new password
         boolean settingPassword = false;
 
-        if (eperson.getRequireCertificate() == false && !StringUtils.isEmpty(request.getParameter("password")))
+        if (!eperson.getRequireCertificate() && !StringUtils.isEmpty(request.getParameter("password")))
         {
             settingPassword = true;
         }
diff --git a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/SimpleSearchServlet.java b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/SimpleSearchServlet.java
index 1e3a60817f..1a2c97dbdb 100644
--- a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/SimpleSearchServlet.java
+++ b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/servlet/SimpleSearchServlet.java
@@ -45,7 +45,6 @@ import java.net.URLEncoder;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
diff --git a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/util/XMLUtil.java b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/util/XMLUtil.java
index 2739430686..65a37f75d3 100644
--- a/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/util/XMLUtil.java
+++ b/dspace-jspui/dspace-jspui-api/src/main/java/org/dspace/app/webui/util/XMLUtil.java
@@ -38,6 +38,7 @@ import java.io.IOException;
 import java.io.StringWriter;
 import java.util.Enumeration;
 import java.util.Hashtable;
+import java.util.Map;
 
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -109,8 +110,7 @@ public class XMLUtil
      * @return the transformed xml document
      * @throws Exception
      */
-    public static Document transformDocument(Document xmlDocument,
-            Hashtable parameters, String xsltFilename) throws Exception
+    public static Document transformDocument(Document xmlDocument, Map<String, String> parameters, String xsltFilename) throws Exception
     {
 
         // Generate a Transformer.
@@ -120,12 +120,9 @@ public class XMLUtil
         // set transformation parameters
         if (parameters != null)
         {
-            Enumeration keys = parameters.keys();
-            while (keys.hasMoreElements())
+            for (Map.Entry<String, String> param : parameters.entrySet())
             {
-                String key = (String) keys.nextElement();
-                String value = (String) parameters.get(key);
-                transformer.setParameter(key, value);
+                transformer.setParameter(param.getKey(), param.getValue());
             }
 
         }
@@ -158,8 +155,7 @@ public class XMLUtil
      * @return the transformed xml document as a string
      * @throws Exception
      */
-    public static String transformDocumentAsString(Document xmlDocument,
-            Hashtable parameters, String xsltFilename) throws Exception
+    public static String transformDocumentAsString(Document xmlDocument, Map<String, String> parameters, String xsltFilename) throws Exception
     {
 
         // Generate a Transformer.
@@ -169,14 +165,10 @@ public class XMLUtil
         // set transformation parameters
         if (parameters != null)
         {
-            Enumeration keys = parameters.keys();
-            while (keys.hasMoreElements())
+            for (Map.Entry<String, String> param : parameters.entrySet())
             {
-                String key = (String) keys.nextElement();
-                String value = (String) parameters.get(key);
-                transformer.setParameter(key, value);
+                transformer.setParameter(param.getKey(), param.getValue());
             }
-
         }
 
         StringWriter stringWriter = new StringWriter();
diff --git a/dspace-stats/src/main/java/org/dspace/statistics/content/DatasetTimeGenerator.java b/dspace-stats/src/main/java/org/dspace/statistics/content/DatasetTimeGenerator.java
index 926f563fde..1ebc91a309 100644
--- a/dspace-stats/src/main/java/org/dspace/statistics/content/DatasetTimeGenerator.java
+++ b/dspace-stats/src/main/java/org/dspace/statistics/content/DatasetTimeGenerator.java
@@ -134,19 +134,19 @@ public class DatasetTimeGenerator extends DatasetGenerator {
     }
 
     public Date getActualStartDate() {
-        return actualStartDate;
+        return actualStartDate == null ? null : (Date)actualStartDate.clone();
     }
 
     public void setActualStartDate(Date actualStartDate) {
-        this.actualStartDate = actualStartDate;
+        this.actualStartDate = actualStartDate == null ? null : (Date)actualStartDate.clone();
     }
 
     public Date getActualEndDate() {
-        return actualEndDate;
+        return actualEndDate == null ? null : (Date)actualEndDate.clone();
     }
 
     public void setActualEndDate(Date actualEndDate) {
-        this.actualEndDate = actualEndDate;
+        this.actualEndDate = actualEndDate == null ? null : (Date)actualEndDate.clone();
     }
 
     public void setDateType(String dateType) {
diff --git a/dspace-stats/src/main/java/org/dspace/statistics/content/filter/StatisticsSolrDateFilter.java b/dspace-stats/src/main/java/org/dspace/statistics/content/filter/StatisticsSolrDateFilter.java
index 71defecf48..e2530deca3 100644
--- a/dspace-stats/src/main/java/org/dspace/statistics/content/filter/StatisticsSolrDateFilter.java
+++ b/dspace-stats/src/main/java/org/dspace/statistics/content/filter/StatisticsSolrDateFilter.java
@@ -47,14 +47,14 @@ public class StatisticsSolrDateFilter implements StatisticsFilter {
      * Must be paired with {@link #setEndDate(Date)}.
      */
     public void setStartDate(Date startDate) {
-        this.startDate = startDate;
+        this.startDate = startDate == null ? null : (Date)startDate.clone();
     }
 
     /** Set the end date as a Date object.
      * Must be paired with {@link #setStartDate(Date)}.
      */
     public void setEndDate(Date endDate) {
-        this.endDate = endDate;
+        this.endDate = endDate == null ? null : (Date)endDate.clone();
     }
 
     /** Convert the date range to a filter expression.
diff --git a/dspace-xmlui/dspace-xmlui-api/src/main/java/org/dspace/app/xmlui/aspect/submission/AbstractStep.java b/dspace-xmlui/dspace-xmlui-api/src/main/java/org/dspace/app/xmlui/aspect/submission/AbstractStep.java
index 95f7cbc735..be7d5bb1e8 100644
--- a/dspace-xmlui/dspace-xmlui-api/src/main/java/org/dspace/app/xmlui/aspect/submission/AbstractStep.java
+++ b/dspace-xmlui/dspace-xmlui-api/src/main/java/org/dspace/app/xmlui/aspect/submission/AbstractStep.java
@@ -44,7 +44,6 @@ import java.io.IOException;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;