diff --git a/.settings-template.xml b/.settings-template.xml
index 3de4a4c4bf1..bc613338be9 100644
--- a/.settings-template.xml
+++ b/.settings-template.xml
@@ -1,6 +1,6 @@
 <settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
+	xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 https://maven.apache.org/xsd/settings-1.0.0.xsd">
 	<profiles>
 		<profile>
 			<id>snapshot</id>
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/META-INF/persistence.xml b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/META-INF/persistence.xml
index 1607abfb578..439d601d8fa 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/META-INF/persistence.xml
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/META-INF/persistence.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
+<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence https://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
 	<persistence-unit name="manually-configured">
 		<class>org.springframework.boot.autoconfigure.orm.jpa.test.City</class>
 		<exclude-unlisted-classes>true</exclude-unlisted-classes>
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/db/changelog/db.changelog-override.xml b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/db/changelog/db.changelog-override.xml
index 2e418cb347d..52c3ccfe5d9 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/db/changelog/db.changelog-override.xml
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/db/changelog/db.changelog-override.xml
@@ -3,8 +3,8 @@
         xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
-        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.0.xsd
-        http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd">
+        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog https://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.0.xsd
+        http://www.liquibase.org/xml/ns/dbchangelog-ext https://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd">
 
     <changeSet id="1" author="marceloverdijk">
         <createTable tableName="customer">
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/early-init-test.xml b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/early-init-test.xml
index 9c28c45026c..2ef5e73d120 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/early-init-test.xml
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/early-init-test.xml
@@ -2,7 +2,7 @@
 
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean id="earlyInit" class="org.springframework.boot.autoconfigure.EarlyInitFactoryBean" >
 		<property name="propertyFromConfig" value="${foo}" />
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/ehcache3.xml b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/ehcache3.xml
index 12ab645b9f4..73d27c811d5 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/ehcache3.xml
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/ehcache3.xml
@@ -3,8 +3,8 @@
 		xmlns='http://www.ehcache.org/v3'
 		xmlns:jsr107='http://www.ehcache.org/v3/jsr107'
 		xsi:schemaLocation="
-        http://www.ehcache.org/v3 http://www.ehcache.org/schema/ehcache-core-3.1.xsd
-        http://www.ehcache.org/v3/jsr107 http://www.ehcache.org/schema/ehcache-107-ext-3.1.xsd">
+        http://www.ehcache.org/v3 https://www.ehcache.org/schema/ehcache-core-3.1.xsd
+        http://www.ehcache.org/v3/jsr107 https://www.ehcache.org/schema/ehcache-107-ext-3.1.xsd">
 
 	<cache-template name="example">
 		<heap unit="entries">200</heap>
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/factorybean.xml b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/factorybean.xml
index bac59ef4f03..a7852de0c25 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/factorybean.xml
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/factorybean.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean id="example"
 		class="org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBeanTests.ExampleFactoryBean">
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/foo.xml b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/foo.xml
index 735b571fc78..80a64071da8 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/foo.xml
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/resources/org/springframework/boot/autoconfigure/condition/foo.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean id="foo" class="java.lang.String">
 		<constructor-arg value="foo" />
diff --git a/spring-boot-project/spring-boot-cli/samples/runner.xml b/spring-boot-project/spring-boot-cli/samples/runner.xml
index 2a8f5aad1a4..ac4fb0599e1 100644
--- a/spring-boot-project/spring-boot-cli/samples/runner.xml
+++ b/spring-boot-project/spring-boot-cli/samples/runner.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean id="runner" class="org.test.Runner"/>
 
diff --git a/spring-boot-project/spring-boot-cli/src/main/assembly/jar-with-dependencies.xml b/spring-boot-project/spring-boot-cli/src/main/assembly/jar-with-dependencies.xml
index a6b47339111..4a4dcdfc693 100644
--- a/spring-boot-project/spring-boot-cli/src/main/assembly/jar-with-dependencies.xml
+++ b/spring-boot-project/spring-boot-cli/src/main/assembly/jar-with-dependencies.xml
@@ -2,7 +2,7 @@
 <assembly
 	xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
+	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 https://maven.apache.org/xsd/assembly-1.1.2.xsd">
 	<id>full</id>
 	<formats>
 		<format>jar</format>
diff --git a/spring-boot-project/spring-boot-cli/src/test/resources/.m2/settings.xml b/spring-boot-project/spring-boot-cli/src/test/resources/.m2/settings.xml
index 86a68acfac1..6cc8d41bd2a 100644
--- a/spring-boot-project/spring-boot-cli/src/test/resources/.m2/settings.xml
+++ b/spring-boot-project/spring-boot-cli/src/test/resources/.m2/settings.xml
@@ -1,12 +1,12 @@
 <settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
-		http://maven.apache.org/xsd/settings-1.0.0.xsd">
+		https://maven.apache.org/xsd/settings-1.0.0.xsd">
 
 	<mirrors>
 		<mirror>
 			<id>central-mirror</id>
-			<url>http://central-mirror.example.com/maven2</url>
+			<url>https://central-mirror.example.com/maven2</url>
 			<mirrorOf>central</mirrorOf>
 		</mirror>
 	</mirrors>
diff --git a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/active-profile-repositories/.m2/settings.xml b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/active-profile-repositories/.m2/settings.xml
index 8cc312378d8..a4bba4bb570 100644
--- a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/active-profile-repositories/.m2/settings.xml
+++ b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/active-profile-repositories/.m2/settings.xml
@@ -3,7 +3,7 @@
 	<mirrors>
 		<mirror>
 			<id>my-mirror</id>
-			<url>http://maven.example.com/mirror</url>
+			<url>https://maven.example.com/mirror</url>
 			<mirrorOf>my-server</mirrorOf>
 		</mirror>
 	</mirrors>
diff --git a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/basic/.m2/settings.xml b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/basic/.m2/settings.xml
index 5439ce8cfb8..b9e5be086d4 100644
--- a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/basic/.m2/settings.xml
+++ b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/basic/.m2/settings.xml
@@ -3,7 +3,7 @@
 	<mirrors>
 		<mirror>
 			<id>my-mirror</id>
-			<url>http://maven.example.com/mirror</url>
+			<url>https://maven.example.com/mirror</url>
 			<mirrorOf>my-server</mirrorOf>
 		</mirror>
 	</mirrors>
@@ -39,7 +39,7 @@
 	    	<repositories>
 	        	<repository>
 	            	<id>example-repository</id>
-	            	<url>http://repo.example.com</url>
+	            	<url>https://repo.example.com</url>
 	        	</repository>
 	    	</repositories>
 		</profile>
diff --git a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/encrypted/.m2/settings.xml b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/encrypted/.m2/settings.xml
index b8701c783a1..5160df56576 100644
--- a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/encrypted/.m2/settings.xml
+++ b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/encrypted/.m2/settings.xml
@@ -3,7 +3,7 @@
 	<mirrors>
 		<mirror>
 			<id>my-mirror</id>
-			<url>http://maven.example.com/mirror</url>
+			<url>https://maven.example.com/mirror</url>
 			<mirrorOf>my-server</mirrorOf>
 		</mirror>
 	</mirrors>
diff --git a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/property-interpolation/.m2/settings.xml b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/property-interpolation/.m2/settings.xml
index 873642e6dd8..a70af0b4c88 100644
--- a/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/property-interpolation/.m2/settings.xml
+++ b/spring-boot-project/spring-boot-cli/src/test/resources/maven-settings/property-interpolation/.m2/settings.xml
@@ -1,7 +1,7 @@
 <settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
-		http://maven.apache.org/xsd/settings-1.0.0.xsd">
+		https://maven.apache.org/xsd/settings-1.0.0.xsd">
 
 	<localRepository>${foo}/repository</localRepository>
 
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl-config.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl-config.xml
index e4d677fc50e..e354da15f10 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl-config.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl-config.xml
@@ -19,5 +19,5 @@
 	<highlighter id="properties" file="./xslthl/properties-hl.xml" />
 	<highlighter id="json" file="./xslthl/json-hl.xml" />
 	<highlighter id="yaml" file="./xslthl/yaml-hl.xml" />
-	<namespace prefix="xslthl" uri="http://xslthl.sf.net" />
+	<namespace prefix="xslthl" uri="http://xslthl.sourceforge.net/" />
 </xslthl-config>
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/bourne-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/bourne-hl.xml
index e2cd98d8b50..90408acc6e9 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/bourne-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/bourne-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for SH
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2010 Mathieu Malaterre
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/c-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/c-hl.xml
index 176cc379ff9..7363dba9118 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/c-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/c-hl.xml
@@ -3,7 +3,7 @@
 Syntax highlighting definition for C
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/cpp-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/cpp-hl.xml
index ef83c4f5eed..b31f7362219 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/cpp-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/cpp-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for C++
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/csharp-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/csharp-hl.xml
index d57e6310296..09373348a51 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/csharp-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/csharp-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for C#
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/css-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/css-hl.xml
index 164c48c3d86..21439ae69d7 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/css-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/css-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for CSS files
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2011-2012 Martin Hujer, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
@@ -26,7 +26,7 @@ freely, subject to the following restrictions:
 Martin Hujer <mhujer at users.sourceforge.net>
 Michiel Hendriks <elmuerte at users.sourceforge.net>
 
-Reference: http://www.w3.org/TR/CSS21/propidx.html
+Reference: https://www.w3.org/TR/CSS21/propidx.html
 
 -->
 <highlighters>
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/html-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/html-hl.xml
index 5b6761bab97..366cd46f22a 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/html-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/html-hl.xml
@@ -7,7 +7,7 @@
   myxml-hl.xml - konfigurace zvyraznovace XML, ktera zvlast zvyrazni
                  HTML elementy a XSL elementy
 
-  This file has been customized for the Asciidoctor project (http://asciidoctor.org).
+  This file has been customized for the Asciidoctor project (https://asciidoctor.org).
 -->
 <highlighters>
   <highlighter type="xml">
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ini-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ini-hl.xml
index 34c103637ed..6bd60b3e308 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ini-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ini-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for ini files
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/java-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/java-hl.xml
index f7bb1641462..4fe3c1fecca 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/java-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/java-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for Java
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/javascript-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/javascript-hl.xml
index 99b8a71e961..91620401fc0 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/javascript-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/javascript-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for JavaScript
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/perl-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/perl-hl.xml
index 73d71cc02cd..c8a4d5902a7 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/perl-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/perl-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for Perl
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/php-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/php-hl.xml
index 1da25b8cc6c..3ea157873b0 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/php-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/php-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for PHP
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/properties-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/properties-hl.xml
index 775f2f13e79..8205aac323e 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/properties-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/properties-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for Java
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/python-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/python-hl.xml
index a4674432391..72bf0dbb1f6 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/python-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/python-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for Python
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ruby-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ruby-hl.xml
index d105640e80a..a2cee724aa2 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ruby-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/ruby-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for Ruby
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2005-2008 Michal Molhanec, Jirka Kosek, Michiel Hendriks
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/sql2003-hl.xml b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/sql2003-hl.xml
index ac1d5d048bc..65c08a36986 100644
--- a/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/sql2003-hl.xml
+++ b/spring-boot-project/spring-boot-docs/src/main/docbook/xsl/xslthl/sql2003-hl.xml
@@ -4,7 +4,7 @@
 Syntax highlighting definition for SQL:1999
 
 xslthl - XSLT Syntax Highlighting
-http://sourceforge.net/projects/xslthl/
+https://sourceforge.net/projects/xslthl/
 Copyright (C) 2012 Michiel Hendriks, Martin Hujer, k42b3
 
 This software is provided 'as-is', without any express or implied
diff --git a/spring-boot-project/spring-boot-starters/src/main/assembly/starter-poms-assembly.xml b/spring-boot-project/spring-boot-starters/src/main/assembly/starter-poms-assembly.xml
index 0a81434a2ff..cbc5e48bec3 100644
--- a/spring-boot-project/spring-boot-starters/src/main/assembly/starter-poms-assembly.xml
+++ b/spring-boot-project/spring-boot-starters/src/main/assembly/starter-poms-assembly.xml
@@ -1,6 +1,6 @@
 <assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 http://maven.apache.org/xsd/assembly-1.1.3.xsd">
+	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 https://maven.apache.org/xsd/assembly-1.1.3.xsd">
 	<id>starter-poms</id>
 	<formats>
 		<format>zip</format>
diff --git a/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/SpringApplicationConfigurationXmlConventionConfigurationTests-context.xml b/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/SpringApplicationConfigurationXmlConventionConfigurationTests-context.xml
index a25ca5b996d..a231d42152f 100644
--- a/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/SpringApplicationConfigurationXmlConventionConfigurationTests-context.xml
+++ b/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/SpringApplicationConfigurationXmlConventionConfigurationTests-context.xml
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
-				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
+				http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
 
 	<bean id="foo" class="java.lang.String">
 		<constructor-arg>
diff --git a/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/context/SpringBootTestXmlConventionConfigurationTests-context.xml b/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/context/SpringBootTestXmlConventionConfigurationTests-context.xml
index a25ca5b996d..a231d42152f 100644
--- a/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/context/SpringBootTestXmlConventionConfigurationTests-context.xml
+++ b/spring-boot-project/spring-boot-test/src/test/resources/org/springframework/boot/test/context/SpringBootTestXmlConventionConfigurationTests-context.xml
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
-				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
+				http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
 
 	<bean id="foo" class="java.lang.String">
 		<constructor-arg>
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-jar/src/main/assembly/jar-with-dependencies.xml b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-jar/src/main/assembly/jar-with-dependencies.xml
index 44626f91aa1..1f7cf8ec13a 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-jar/src/main/assembly/jar-with-dependencies.xml
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-jar/src/main/assembly/jar-with-dependencies.xml
@@ -2,7 +2,7 @@
 <assembly
 	xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
+	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 https://maven.apache.org/xsd/assembly-1.1.2.xsd">
 	<id>full</id>
 	<formats>
 		<format>jar</format>
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/app.xml b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/app.xml
index d332aebc34d..83a4f927e24 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/app.xml
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/app.xml
@@ -2,7 +2,7 @@
 <assembly
 	xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
+	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 https://maven.apache.org/xsd/assembly-1.1.2.xsd">
 	<id>app</id>
 	<formats>
 		<format>jar</format>
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/dependencies.xml b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/dependencies.xml
index 5044392b3e9..306b55e4e9c 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/dependencies.xml
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props-lib/src/main/assembly/dependencies.xml
@@ -2,7 +2,7 @@
 <assembly
 	xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
+	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 https://maven.apache.org/xsd/assembly-1.1.2.xsd">
 	<id>dependencies</id>
 	<formats>
 		<format>jar</format>
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props/src/main/assembly/jar-with-dependencies.xml b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props/src/main/assembly/jar-with-dependencies.xml
index 1120acb7e2f..2dbf0f3a502 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props/src/main/assembly/jar-with-dependencies.xml
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/it/executable-props/src/main/assembly/jar-with-dependencies.xml
@@ -2,7 +2,7 @@
 <assembly
 	xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
+	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 https://maven.apache.org/xsd/assembly-1.1.2.xsd">
 	<id>full</id>
 	<formats>
 		<format>jar</format>
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/resources/root/META-INF/spring/application.xml b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/resources/root/META-INF/spring/application.xml
index 704859f0492..cf04aa4fbe4 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/resources/root/META-INF/spring/application.xml
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/resources/root/META-INF/spring/application.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 </beans>
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/site.xml b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/site.xml
index 2ecc646ecab..dc619012c22 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/site.xml
+++ b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/site/site.xml
@@ -1,5 +1,5 @@
 <project xmlns="http://maven.apache.org/DECORATION/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-		 xsi:schemaLocation="http://maven.apache.org/DECORATION/1.0.0 http://maven.apache.org/xsd/decoration-1.0.0.xsd">
+		 xsi:schemaLocation="http://maven.apache.org/DECORATION/1.0.0 https://maven.apache.org/xsd/decoration-1.0.0.xsd">
 	<body>
 		<menu name="Overview">
 			<item name="Introduction" href="index.html"/>
diff --git a/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/context/embedded/tomcat/empty-web.xml b/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/context/embedded/tomcat/empty-web.xml
index 14c04a59579..4ec3f71a4bc 100644
--- a/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/context/embedded/tomcat/empty-web.xml
+++ b/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/context/embedded/tomcat/empty-web.xml
@@ -2,5 +2,5 @@
 <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
-	http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
+	https://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 </web-app>
diff --git a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/context/properties/testProperties.xml b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/context/properties/testProperties.xml
index a8ecd1a55af..b7dc32185af 100644
--- a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/context/properties/testProperties.xml
+++ b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/context/properties/testProperties.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean
 		id="org.springframework.boot.context.properties.ConfigurationPropertiesTests$BasicProperties"
diff --git a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/consumer.xml b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/consumer.xml
index 9440e1af13d..cf74f72245c 100644
--- a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/consumer.xml
+++ b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/consumer.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean class="org.springframework.boot.diagnostics.analyzer.nounique.TestBeanConsumer"/>
 
diff --git a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/producer.xml b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/producer.xml
index 3b28fb030db..f1f3de4abb6 100644
--- a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/producer.xml
+++ b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/diagnostics/analyzer/nounique/producer.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean class="org.springframework.boot.diagnostics.analyzer.nounique.TestBean" name="xmlTestBean"/>
 
diff --git a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/sample-beans.xml b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/sample-beans.xml
index f0fb6ce5138..f66853848fe 100644
--- a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/sample-beans.xml
+++ b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/sample-beans.xml
@@ -2,8 +2,8 @@
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xmlns:context="http://www.springframework.org/schema/context"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
-				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
+				http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
 
 	<bean id="myXmlComponent" class="org.springframework.boot.sampleconfig.MyComponent"/>
 </beans>
diff --git a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/web/servlet/context/exampleEmbeddedWebApplicationConfiguration.xml b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/web/servlet/context/exampleEmbeddedWebApplicationConfiguration.xml
index 92367a6fa89..e220798078e 100644
--- a/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/web/servlet/context/exampleEmbeddedWebApplicationConfiguration.xml
+++ b/spring-boot-project/spring-boot/src/test/resources/org/springframework/boot/web/servlet/context/exampleEmbeddedWebApplicationConfiguration.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
 
 	<bean name="servletContainerFactory"
 		class="org.springframework.boot.web.servlet.server.MockServletWebServerFactory" />
diff --git a/spring-boot-samples/spring-boot-sample-cache/src/main/resources/ehcache3.xml b/spring-boot-samples/spring-boot-sample-cache/src/main/resources/ehcache3.xml
index df1a92a60d4..cce17bb79e1 100644
--- a/spring-boot-samples/spring-boot-sample-cache/src/main/resources/ehcache3.xml
+++ b/spring-boot-samples/spring-boot-sample-cache/src/main/resources/ehcache3.xml
@@ -1,8 +1,8 @@
 <config xmlns='http://www.ehcache.org/v3'
 		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 		xmlns:jsr107="http://www.ehcache.org/v3/jsr107"
-		xsi:schemaLocation="http://www.ehcache.org/v3 http://www.ehcache.org/schema/ehcache-core-3.0.xsd
-							http://www.ehcache.org/v3/jsr107 http://www.ehcache.org/schema/ehcache-107-ext-3.0.xsd">
+		xsi:schemaLocation="http://www.ehcache.org/v3 https://www.ehcache.org/schema/ehcache-core-3.0.xsd
+							http://www.ehcache.org/v3/jsr107 https://www.ehcache.org/schema/ehcache-107-ext-3.0.xsd">
 	<cache alias="countries">
 		<expiry>
 			<ttl unit="seconds">600</ttl>
diff --git a/spring-boot-samples/spring-boot-sample-traditional/src/main/webapp/WEB-INF/web.xml b/spring-boot-samples/spring-boot-sample-traditional/src/main/webapp/WEB-INF/web.xml
index b7db2409322..6fc387aeaf7 100644
--- a/spring-boot-samples/spring-boot-sample-traditional/src/main/webapp/WEB-INF/web.xml
+++ b/spring-boot-samples/spring-boot-sample-traditional/src/main/webapp/WEB-INF/web.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
+	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee https://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 
 	<servlet>
 		<servlet-name>appServlet</servlet-name>
diff --git a/spring-boot-samples/spring-boot-sample-xml/src/main/resources/META-INF/application-context.xml b/spring-boot-samples/spring-boot-sample-xml/src/main/resources/META-INF/application-context.xml
index dcc6e4b20bb..f080646aa12 100644
--- a/spring-boot-samples/spring-boot-sample-xml/src/main/resources/META-INF/application-context.xml
+++ b/spring-boot-samples/spring-boot-sample-xml/src/main/resources/META-INF/application-context.xml
@@ -2,8 +2,8 @@
 <beans xmlns="http://www.springframework.org/schema/beans"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xmlns:context="http://www.springframework.org/schema/context"
-	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
-				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
+	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
+				http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
 
 	<context:annotation-config/>
 	<context:property-placeholder/>
diff --git a/spring-boot-tests/spring-boot-integration-tests/spring-boot-server-tests/src/test/resources/pom-template.xml b/spring-boot-tests/spring-boot-integration-tests/spring-boot-server-tests/src/test/resources/pom-template.xml
index b9f0411a4d0..9d880aa7f7b 100644
--- a/spring-boot-tests/spring-boot-integration-tests/spring-boot-server-tests/src/test/resources/pom-template.xml
+++ b/spring-boot-tests/spring-boot-integration-tests/spring-boot-server-tests/src/test/resources/pom-template.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <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/xsd/maven-4.0.0.xsd">
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<parent>
 		<groupId>org.springframework.boot</groupId>
diff --git a/src/checkstyle/checkstyle-suppressions.xml b/src/checkstyle/checkstyle-suppressions.xml
index b8d737e1ba1..70d3272dd3c 100644
--- a/src/checkstyle/checkstyle-suppressions.xml
+++ b/src/checkstyle/checkstyle-suppressions.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE suppressions PUBLIC
-    "-//Puppy Crawl//DTD Suppressions 1.1//EN"
-    "http://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
+    "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
+    "https://checkstyle.org/dtds/suppressions_1_2.dtd">
 <suppressions>
 	<suppress files="SpringApplicationTests\.java" checks="FinalClass" />
 	<suppress files=".+Configuration\.java" checks="HideUtilityClassConstructor" />