diff --git a/src/main/java/com/jcabi/jdbc/JdbcSession.java b/src/main/java/com/jcabi/jdbc/JdbcSession.java
index 6761bc1..b988cd0 100644
--- a/src/main/java/com/jcabi/jdbc/JdbcSession.java
+++ b/src/main/java/com/jcabi/jdbc/JdbcSession.java
@@ -34,6 +34,7 @@
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Collection;
+import java.util.LinkedList;
 import java.util.UUID;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicReference;
@@ -188,8 +189,8 @@ public final class JdbcSession {
      */
     @SuppressWarnings("PMD.ConstructorOnlyInitializesOrCallOtherConstructors")
     public JdbcSession(final DataSource src) {
-        this.args = new CopyOnWriteArrayList<>();
-        this.preparations = new CopyOnWriteArrayList<>();
+        this.args = new LinkedList<>();
+        this.preparations = new LinkedList<>();
         this.connection = new AtomicReference<>();
         this.auto = true;
         this.source = src;
@@ -251,7 +252,9 @@ public JdbcSession autocommit(final boolean autocommit) {
      * @return This object
      */
     public JdbcSession set(final Object value) {
-        this.args.add(value);
+        synchronized (this.args) {
+            this.args.add(value);
+        }
         return this;
     }