diff --git a/jOOQ/src/main/java/org/jooq/util/cubrid/CUBRIDDSL.java b/jOOQ/src/main/java/org/jooq/util/cubrid/CUBRIDDSL.java
index 71d208105a..fa0eca356d 100644
--- a/jOOQ/src/main/java/org/jooq/util/cubrid/CUBRIDDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/cubrid/CUBRIDDSL.java
@@ -54,7 +54,7 @@ public class CUBRIDDSL extends DSL {
     /**
      * No instances
      */
-    private CUBRIDDSL() {
+    protected CUBRIDDSL() {
     }
 
     // -------------------------------------------------------------------------
diff --git a/jOOQ/src/main/java/org/jooq/util/derby/DerbyDSL.java b/jOOQ/src/main/java/org/jooq/util/derby/DerbyDSL.java
index da8a2b651a..f5f6f26ed7 100644
--- a/jOOQ/src/main/java/org/jooq/util/derby/DerbyDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/derby/DerbyDSL.java
@@ -53,6 +53,6 @@ public class DerbyDSL extends DSL {
     /**
      * No instances
      */
-    private DerbyDSL() {
+    protected DerbyDSL() {
     }
 }
\ No newline at end of file
diff --git a/jOOQ/src/main/java/org/jooq/util/firebird/FirebirdDSL.java b/jOOQ/src/main/java/org/jooq/util/firebird/FirebirdDSL.java
index 6c0af25edc..2694746350 100644
--- a/jOOQ/src/main/java/org/jooq/util/firebird/FirebirdDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/firebird/FirebirdDSL.java
@@ -53,6 +53,6 @@ public class FirebirdDSL extends DSL {
     /**
      * No instances
      */
-    private FirebirdDSL() {
+    protected FirebirdDSL() {
     }
 }
diff --git a/jOOQ/src/main/java/org/jooq/util/h2/H2DSL.java b/jOOQ/src/main/java/org/jooq/util/h2/H2DSL.java
index 88d45cfb9b..94c8e046ab 100644
--- a/jOOQ/src/main/java/org/jooq/util/h2/H2DSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/h2/H2DSL.java
@@ -53,6 +53,6 @@ public class H2DSL extends DSL {
     /**
      * No instances
      */
-    private H2DSL() {
+    protected H2DSL() {
     }
 }
diff --git a/jOOQ/src/main/java/org/jooq/util/hsqldb/HSQLDBDSL.java b/jOOQ/src/main/java/org/jooq/util/hsqldb/HSQLDBDSL.java
index a7a31e6031..aaaf8876b4 100644
--- a/jOOQ/src/main/java/org/jooq/util/hsqldb/HSQLDBDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/hsqldb/HSQLDBDSL.java
@@ -53,6 +53,6 @@ public class HSQLDBDSL extends DSL {
     /**
      * No instances
      */
-    private HSQLDBDSL() {
+    protected HSQLDBDSL() {
     }
 }
diff --git a/jOOQ/src/main/java/org/jooq/util/mariadb/MariaDBDSL.java b/jOOQ/src/main/java/org/jooq/util/mariadb/MariaDBDSL.java
index 51d041f2ee..8153faa4e7 100644
--- a/jOOQ/src/main/java/org/jooq/util/mariadb/MariaDBDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/mariadb/MariaDBDSL.java
@@ -55,7 +55,7 @@ public class MariaDBDSL extends DSL {
     /**
      * No instances
      */
-    private MariaDBDSL() {
+    protected MariaDBDSL() {
     }
 
     // -------------------------------------------------------------------------
diff --git a/jOOQ/src/main/java/org/jooq/util/mysql/MySQLDSL.java b/jOOQ/src/main/java/org/jooq/util/mysql/MySQLDSL.java
index b15a80b46f..68b8f2a96a 100644
--- a/jOOQ/src/main/java/org/jooq/util/mysql/MySQLDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/mysql/MySQLDSL.java
@@ -55,7 +55,7 @@ public class MySQLDSL extends DSL {
     /**
      * No instances
      */
-    private MySQLDSL() {
+    protected MySQLDSL() {
     }
 
     // -------------------------------------------------------------------------
diff --git a/jOOQ/src/main/java/org/jooq/util/postgres/PostgresDSL.java b/jOOQ/src/main/java/org/jooq/util/postgres/PostgresDSL.java
index afc38c9b06..1b39230ffc 100644
--- a/jOOQ/src/main/java/org/jooq/util/postgres/PostgresDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/postgres/PostgresDSL.java
@@ -63,7 +63,7 @@ public class PostgresDSL extends DSL {
     /**
      * No instances
      */
-    private PostgresDSL() {}
+    protected PostgresDSL() {}
 
     // -------------------------------------------------------------------------
     // PostgreSQL-specific array functions
diff --git a/jOOQ/src/main/java/org/jooq/util/sqlite/SQLiteDSL.java b/jOOQ/src/main/java/org/jooq/util/sqlite/SQLiteDSL.java
index 534f0165ac..84453ece50 100644
--- a/jOOQ/src/main/java/org/jooq/util/sqlite/SQLiteDSL.java
+++ b/jOOQ/src/main/java/org/jooq/util/sqlite/SQLiteDSL.java
@@ -54,7 +54,7 @@ public class SQLiteDSL extends DSL {
     /**
      * No instances
      */
-    private SQLiteDSL() {
+    protected SQLiteDSL() {
     }
 
     // -------------------------------------------------------------------------