Index: com/ziclix/python/sql/PyConnection.java
===================================================================
--- com/ziclix/python/sql/PyConnection.java	(Revision 6988)
+++ com/ziclix/python/sql/PyConnection.java	(Arbeitskopie)
@@ -13,6 +13,7 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.WeakHashMap;
 
 import org.python.core.ClassDictInit;
 import org.python.core.Py;
@@ -50,11 +51,15 @@
     /** The underlying java.sql.Connection. */
     protected Connection connection;
 
-    /** Underlying cursors. */
-    private Set<PyCursor> cursors;
+    /** Underlying cursors. 
+     * 
+     * Note: the appropriate container would be a WeakHashSet, 
+     * but the Java runtime does not provide that type. 
+     * */
+    private WeakHashMap<PyCursor, Boolean> cursors;
 
     /** Underlying statements. */
-    private Set<PyStatement> statements;
+    private WeakHashMap<PyStatement, Boolean> statements;
 
     /** Field __members__ */
     protected static PyList __members__;
@@ -93,9 +98,9 @@
      */
     public PyConnection(Connection connection) throws SQLException {
         this.closed = false;
-        this.cursors = new HashSet<PyCursor>();
+        this.cursors = new WeakHashMap<PyCursor, Boolean>();
         this.connection = connection;
-        this.statements = new HashSet<PyStatement>();
+        this.statements = new WeakHashMap<PyStatement, Boolean>();
         this.supportsTransactions = this.connection.getMetaData().supportsTransactions();
         this.supportsMultipleResultSets =
                 this.connection.getMetaData().supportsMultipleResultSets();
@@ -223,9 +228,9 @@
         } else if ("__connection__".equals(name)) {
             return Py.java2py(this.connection);
         } else if ("__cursors__".equals(name)) {
-            return Py.java2py(Collections.unmodifiableSet(this.cursors));
+            return Py.java2py(Collections.unmodifiableSet(this.cursors.keySet()));
         } else if ("__statements__".equals(name)) {
-            return Py.java2py(Collections.unmodifiableSet(this.statements));
+            return Py.java2py(Collections.unmodifiableSet(this.statements.keySet()));
         } else if ("__methods__".equals(name)) {
             return __methods__;
         } else if ("__members__".equals(name)) {
@@ -253,14 +258,14 @@
         this.closed = true;
 
         synchronized (this.cursors) {
-            for (PyCursor cursor: cursors) {
+            for (PyCursor cursor: cursors.keySet()) {
                 cursor.close();
             }
             this.cursors.clear();
         }
 
         synchronized (this.statements) {
-            for (PyStatement statement : statements) {
+            for (PyStatement statement : statements.keySet()) {
                 statement.close();
             }
             this.statements.clear();
@@ -387,7 +392,7 @@
         }
 
         PyCursor cursor = new PyExtendedCursor(this, dynamicFetch, rsType, rsConcur);
-        this.cursors.add(cursor);
+        this.cursors.put(cursor,Boolean.TRUE);
         return cursor;
     }
 
@@ -400,7 +405,9 @@
         if (closed) {
             return;
         }
-        this.cursors.remove(cursor);
+        synchronized (this.cursors) {
+            this.cursors.remove(cursor);			
+		}
     }
 
     /**
@@ -412,7 +419,9 @@
         if (closed) {
             return;
         }
-        this.statements.add(statement);
+        synchronized (this.statements) {
+            this.statements.put(statement, Boolean.TRUE);			
+		}
     }
 
     /**
@@ -425,7 +434,9 @@
         if (closed) {
             return false;
         }
-        return this.statements.contains(statement);
+        synchronized (this.statements) {
+        	return this.statements.containsKey(statement);
+        }
     }
 
     public PyObject __enter__(ThreadState ts) {