diff --git a/confectory-core/src/main/java/net/obvj/confectory/source/StringSource.java b/confectory-core/src/main/java/net/obvj/confectory/source/StringSource.java
index 149e1960..ece89945 100644
--- a/confectory-core/src/main/java/net/obvj/confectory/source/StringSource.java
+++ b/confectory-core/src/main/java/net/obvj/confectory/source/StringSource.java
@@ -20,6 +20,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Objects;
+import java.util.UUID;
 
 import net.obvj.confectory.ConfigurationSourceException;
 import net.obvj.confectory.mapper.Mapper;
@@ -32,6 +33,7 @@
  */
 public class StringSource<T> extends AbstractSource<T> implements Source<T>
 {
+    private final String uuid;
     /**
      * Builds a new configuration source from the specified string.
      *
@@ -40,6 +42,7 @@ public class StringSource<T> extends AbstractSource<T> implements Source<T>
     public StringSource(String source)
     {
         super(Objects.requireNonNull(source, "The source string must not be null"));
+        uuid = UUID.randomUUID().toString();
     }
 
     @Override
@@ -56,4 +59,10 @@ public T load(Mapper<T> mapper)
         }
     }
 
+    @Override
+    public String toString()
+    {
+        return new StringBuilder().append(getClass().getSimpleName()).append("(").append(uuid).append(")")
+              .toString();
+    }
 }
diff --git a/confectory-core/src/test/java/net/obvj/confectory/ConfigurationTest.java b/confectory-core/src/test/java/net/obvj/confectory/ConfigurationTest.java
index 4e9c5b42..7e94430f 100644
--- a/confectory-core/src/test/java/net/obvj/confectory/ConfigurationTest.java
+++ b/confectory-core/src/test/java/net/obvj/confectory/ConfigurationTest.java
@@ -96,10 +96,10 @@ void equalsAndHashCode_notSimilarObjectsPlacedInAHashSet_differentObject()
     void toString_validString()
     {
         assertThat(CONFIG_NS1_STRING_1.toString().replaceAll("\"", ""),
-                containsAll("namespace:" + NAMESPACE1, "source:" + SOURCE_STRING1, "precedence:1"));
+                containsAll("namespace:" + NAMESPACE1, "source:StringSource", "precedence:1"));
 
         assertThat(CONFIG_NS1_STRING_1B.toString().replaceAll("\"", ""),
-                containsAll("namespace:" + NAMESPACE1, "source:" + SOURCE_STRING1, "precedence:2"));
+                containsAll("namespace:" + NAMESPACE1, "source:StringSource", "precedence:2"));
     }
 
     @Test