diff --git a/common/source/java/ch/systemsx/cisd/common/highwatermark/FileWithHighwaterMark.java b/common/source/java/ch/systemsx/cisd/common/highwatermark/FileWithHighwaterMark.java
index 744cb5b5e978f8cb06789747de11e2b3e701ebdc..408635aacbf07dc6ed25b7d415fe11f887a2efda 100644
--- a/common/source/java/ch/systemsx/cisd/common/highwatermark/FileWithHighwaterMark.java
+++ b/common/source/java/ch/systemsx/cisd/common/highwatermark/FileWithHighwaterMark.java
@@ -17,6 +17,7 @@
 package ch.systemsx.cisd.common.highwatermark;
 
 import java.io.File;
+import java.io.Serializable;
 import java.util.Properties;
 
 import org.apache.commons.lang.StringUtils;
@@ -31,9 +32,11 @@ import ch.systemsx.cisd.common.utilities.PropertyUtils;
  * 
  * @author Christian Ribeaud
  */
-public final class FileWithHighwaterMark extends AbstractHashable
+public final class FileWithHighwaterMark extends AbstractHashable implements Serializable
 {
 
+    private static final long serialVersionUID = 1L;
+
     /**
      * The property name under which you must find a <code>long</code> for the high water mark (in
      * <i>kilobytes</i>).
diff --git a/common/source/java/ch/systemsx/cisd/common/highwatermark/HighwaterMarkWatcher.java b/common/source/java/ch/systemsx/cisd/common/highwatermark/HighwaterMarkWatcher.java
index 5e745acd21296d661de0d3ea1501684e42c49994..3dc7b938a67d9a682efbc9ac91593cd976b1a22b 100644
--- a/common/source/java/ch/systemsx/cisd/common/highwatermark/HighwaterMarkWatcher.java
+++ b/common/source/java/ch/systemsx/cisd/common/highwatermark/HighwaterMarkWatcher.java
@@ -18,6 +18,7 @@ package ch.systemsx.cisd.common.highwatermark;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.Serializable;
 
 import javax.swing.event.ChangeEvent;
 import javax.swing.event.ChangeListener;
@@ -231,8 +232,10 @@ public final class HighwaterMarkWatcher implements Runnable
         }
     }
 
-    public final static class HighwaterMarkState
+    public final static class HighwaterMarkState implements Serializable
     {
+        private static final long serialVersionUID = 1L;
+
         private final FileWithHighwaterMark fileWithHighwaterMark;
 
         private final long freeSpace;
diff --git a/common/source/java/ch/systemsx/cisd/common/process/ProcessExecutionHelper.java b/common/source/java/ch/systemsx/cisd/common/process/ProcessExecutionHelper.java
index 851d68e3bfd6bdc1e1c138bd7abfbe53e94e126c..26e837ec28d47e692227c192b8b76b564a6d9fe6 100644
--- a/common/source/java/ch/systemsx/cisd/common/process/ProcessExecutionHelper.java
+++ b/common/source/java/ch/systemsx/cisd/common/process/ProcessExecutionHelper.java
@@ -227,7 +227,10 @@ public final class ProcessExecutionHelper
         } finally
         {
             closeStreams(process);
-            process.destroy();
+            if (process != null)
+            {
+                process.destroy();
+            }
         }
     }
 
@@ -254,7 +257,10 @@ public final class ProcessExecutionHelper
         } finally
         {
             closeStreams(process);
-            process.destroy();
+            if (process != null)
+            {
+                process.destroy();
+            }
         }
     }
 
diff --git a/common/source/java/ch/systemsx/cisd/common/process/ProcessWatchdog.java b/common/source/java/ch/systemsx/cisd/common/process/ProcessWatchdog.java
index b0657de329f2b297e90c5bfc60b08d2677adc4d9..df5cacda0506560c515381887ca4f70b5c79a3dc 100644
--- a/common/source/java/ch/systemsx/cisd/common/process/ProcessWatchdog.java
+++ b/common/source/java/ch/systemsx/cisd/common/process/ProcessWatchdog.java
@@ -124,7 +124,7 @@ public final class ProcessWatchdog implements Runnable
     // Runnable
     //
 
-    public final void run()
+    public final synchronized void run()
     {
         try
         {
diff --git a/common/sourceTest/java/ch/systemsx/cisd/common/utilities/PropertyUtilsTest.java b/common/sourceTest/java/ch/systemsx/cisd/common/utilities/PropertyUtilsTest.java
index bb17bc4865b6c4768c1f3a57d31b494605f724e8..e2508de574ea2c11dd25c6f3bdb3e13402f14f0c 100644
--- a/common/sourceTest/java/ch/systemsx/cisd/common/utilities/PropertyUtilsTest.java
+++ b/common/sourceTest/java/ch/systemsx/cisd/common/utilities/PropertyUtilsTest.java
@@ -79,7 +79,7 @@ public final class PropertyUtilsTest
             PropertyUtils.getMandatoryProperty(properties, propertyKey);
         } catch (final ConfigurationFailureException ex)
         {
-            assertEquals(String.format(PropertyUtils.EMPTY_STRING_FORMAT, propertyKey, "[]"), ex
+            assertEquals(String.format(PropertyUtils.EMPTY_STRING_FORMAT, propertyKey), ex
                     .getMessage());
         }
         final String value = "value";