diff --git a/commons-rng-bom/pom.xml b/commons-rng-bom/pom.xml
index 77e6b906..c852087e 100644
--- a/commons-rng-bom/pom.xml
+++ b/commons-rng-bom/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-bom/src/main/resources-filtered/bom.xml b/commons-rng-bom/src/main/resources-filtered/bom.xml
index f7163958..9a17f925 100644
--- a/commons-rng-bom/src/main/resources-filtered/bom.xml
+++ b/commons-rng-bom/src/main/resources-filtered/bom.xml
@@ -18,7 +18,7 @@
 <project
   xmlns="http://maven.apache.org/POM/4.0.0"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>${project.groupId}</groupId>
diff --git a/commons-rng-client-api/pom.xml b/commons-rng-client-api/pom.xml
index d18570c2..f56e6f6d 100644
--- a/commons-rng-client-api/pom.xml
+++ b/commons-rng-client-api/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-core/pom.xml b/commons-rng-core/pom.xml
index bb8bac2a..f0de437e 100644
--- a/commons-rng-core/pom.xml
+++ b/commons-rng-core/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-docs/pom.xml b/commons-rng-docs/pom.xml
index c7ef024e..02d400a4 100644
--- a/commons-rng-docs/pom.xml
+++ b/commons-rng-docs/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-jmh/pom.xml b/commons-rng-examples/examples-jmh/pom.xml
index 91620b9c..d3c572cf 100644
--- a/commons-rng-examples/examples-jmh/pom.xml
+++ b/commons-rng-examples/examples-jmh/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-jpms/jpms-app/pom.xml b/commons-rng-examples/examples-jpms/jpms-app/pom.xml
index f083c895..38fd7caf 100644
--- a/commons-rng-examples/examples-jpms/jpms-app/pom.xml
+++ b/commons-rng-examples/examples-jpms/jpms-app/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-jpms/jpms-lib/pom.xml b/commons-rng-examples/examples-jpms/jpms-lib/pom.xml
index d947cc02..9b78834d 100644
--- a/commons-rng-examples/examples-jpms/jpms-lib/pom.xml
+++ b/commons-rng-examples/examples-jpms/jpms-lib/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-jpms/pom.xml b/commons-rng-examples/examples-jpms/pom.xml
index c8a7ed9e..49440827 100644
--- a/commons-rng-examples/examples-jpms/pom.xml
+++ b/commons-rng-examples/examples-jpms/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-quadrature/pom.xml b/commons-rng-examples/examples-quadrature/pom.xml
index 98bdf508..727882c5 100644
--- a/commons-rng-examples/examples-quadrature/pom.xml
+++ b/commons-rng-examples/examples-quadrature/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-sampling/pom.xml b/commons-rng-examples/examples-sampling/pom.xml
index 46f5e975..ddc6025c 100644
--- a/commons-rng-examples/examples-sampling/pom.xml
+++ b/commons-rng-examples/examples-sampling/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/examples-stress/pom.xml b/commons-rng-examples/examples-stress/pom.xml
index b4ed8202..07e72b21 100644
--- a/commons-rng-examples/examples-stress/pom.xml
+++ b/commons-rng-examples/examples-stress/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-examples/pom.xml b/commons-rng-examples/pom.xml
index c7cefe97..c332f013 100644
--- a/commons-rng-examples/pom.xml
+++ b/commons-rng-examples/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-integration/pom.xml b/commons-rng-integration/pom.xml
index 56ec5f32..26d97f3c 100644
--- a/commons-rng-integration/pom.xml
+++ b/commons-rng-integration/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-sampling/pom.xml b/commons-rng-sampling/pom.xml
index d10d852d..2ab6ff7a 100644
--- a/commons-rng-sampling/pom.xml
+++ b/commons-rng-sampling/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/commons-rng-simple/pom.xml b/commons-rng-simple/pom.xml
index 4ba02898..88761e41 100644
--- a/commons-rng-simple/pom.xml
+++ b/commons-rng-simple/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/dist-archive/pom.xml b/dist-archive/pom.xml
index c4e601b9..5955a089 100644
--- a/dist-archive/pom.xml
+++ b/dist-archive/pom.xml
@@ -17,7 +17,7 @@ KIND, either express or implied.  See the License for the
 specific language governing permissions and limitations
 under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
diff --git a/pom.xml b/pom.xml
index f7d177f7..413caee3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
     <groupId>org.apache.commons</groupId>
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 033b90f5..10ccd8f9 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -47,7 +47,7 @@ If the output is not quite correct, check for invisible trailing spaces!
 
 <document xmlns="http://maven.apache.org/changes/1.0.0"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-          xsi:schemaLocation="http://maven.apache.org/changes/1.0.0 http://maven.apache.org/xsd/changes-1.0.0.xsd">
+          xsi:schemaLocation="http://maven.apache.org/changes/1.0.0 https://maven.apache.org/xsd/changes-1.0.0.xsd">
   <properties>
     <title>Apache Commons RNG Release Notes</title>
   </properties>
diff --git a/src/conf/pmd/pmd-ruleset.xml b/src/conf/pmd/pmd-ruleset.xml
index afa7bb9b..1841ac53 100644
--- a/src/conf/pmd/pmd-ruleset.xml
+++ b/src/conf/pmd/pmd-ruleset.xml
@@ -18,7 +18,7 @@
 <ruleset name="commons-rng-customized"
     xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 http://pmd.sourceforge.net/ruleset_2_0_0.xsd">
+    xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.net/ruleset_2_0_0.xsd">
   <description>
     This ruleset checks the code for discouraged programming constructs.
   </description>
diff --git a/src/site/site.xml b/src/site/site.xml
index 3cdfecf6..a1ff1a7c 100644
--- a/src/site/site.xml
+++ b/src/site/site.xml
@@ -18,7 +18,7 @@
 <project name="RNG"
     xmlns="http://maven.apache.org/DECORATION/1.6.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/DECORATION/1.6.0 http://maven.apache.org/xsd/decoration-1.6.0.xsd">
+    xsi:schemaLocation="http://maven.apache.org/DECORATION/1.6.0 https://maven.apache.org/xsd/decoration-1.6.0.xsd">
   <bannerRight>
     <name>Apache Commons RNG</name>
     <!-- Use a full URL allows a correct banner for the modules. -->