diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index 4be4ecfbbf..d35de1a7ca 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -40,7 +40,7 @@ Project maintainers who do not follow or enforce the Code of Conduct in good fai
 
 ## Attribution
 
-This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [http://contributor-covenant.org/version/1/4][version]
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [https://contributor-covenant.org/version/1/4][version]
 
-[homepage]: http://contributor-covenant.org
-[version]: http://contributor-covenant.org/version/1/4/
+[homepage]: https://contributor-covenant.org
+[version]: https://contributor-covenant.org/version/1/4/
diff --git a/README.md b/README.md
index 2a51b156d5..a5a389c9d1 100644
--- a/README.md
+++ b/README.md
@@ -108,6 +108,6 @@ extra('wtp.EclipseWtpFormatterStep')             +'{{yes}}       | {{yes}}
 - Thanks to Gábor Bernát for improvements to logging and multi-project support.
 - Thanks to Andrew Oberstar for improvements to formatting java source in non-java source sets. [PR #60](https://github.com/diffplug/spotless/pull/60).
 - Import ordering from [EclipseCodeFormatter](https://github.com/krasa/EclipseCodeFormatter).
-- Built by [gradle](http://gradle.org/).
-- Tested by [junit](http://junit.org/).
-- Maintained by [DiffPlug](http://www.diffplug.com/).
+- Built by [gradle](https://gradle.org/).
+- Tested by [junit](https://junit.org/).
+- Maintained by [DiffPlug](https://www.diffplug.com/).
diff --git a/gradle/java-publish.gradle b/gradle/java-publish.gradle
index 29beac4452..4441e894db 100644
--- a/gradle/java-publish.gradle
+++ b/gradle/java-publish.gradle
@@ -20,7 +20,7 @@ javadoc {
 // use markdown in javadoc
 def makeLink = { url, text -> "<a href=\"${url}\" style=\"text-transform: none;\">${text}</a>" }
 def javadocInfo = '<h2>' + makeLink("https://github.com/${org}/${name}", "${group}:${project.ext.artifactId}:${ext.version}") +
-		' by ' + makeLink('http://www.diffplug.com', 'DiffPlug') + '</h2>'
+		' by ' + makeLink('https://www.diffplug.com', 'DiffPlug') + '</h2>'
 
 String version_str = ext.version.endsWith('-SNAPSHOT') ? 'snapshot' : ext.version
 apply plugin: 'ch.raffael.pegdown-doclet'
@@ -95,7 +95,7 @@ model {
 						licenses {
 							license {
 								name 'The Apache Software License, Version 2.0'
-								url 'http://www.apache.org/license/LICENSE-2.0.txt'
+								url 'https://www.apache.org/license/LICENSE-2.0.txt'
 								distribution 'repo'
 							}
 						}
diff --git a/plugin-gradle/README.md b/plugin-gradle/README.md
index 4dc3c0870f..946610deda 100644
--- a/plugin-gradle/README.md
+++ b/plugin-gradle/README.md
@@ -3,7 +3,7 @@
 <!---freshmark shields
 output = [
   link(shield('Gradle plugin', 'plugins.gradle.org', 'com.diffplug.gradle.spotless', 'blue'), 'https://plugins.gradle.org/plugin/com.diffplug.gradle.spotless'),
-  link(shield('Maven central', 'mavencentral', 'com.diffplug.gradle.spotless:spotless', 'blue'), 'http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-plugin-gradle%22'),
+  link(shield('Maven central', 'mavencentral', 'com.diffplug.gradle.spotless:spotless', 'blue'), 'https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-plugin-gradle%22'),
   link(shield('Javadoc', 'javadoc', '{{stableGradle}}', 'blue'), 'https://{{org}}.github.io/{{name}}/javadoc/spotless-plugin-gradle/{{stableGradle}}/'),
   '',
   link(shield('Changelog', 'changelog', '{{versionGradle}}', 'brightgreen'), 'CHANGES.md'),
@@ -13,7 +13,7 @@ output = [
   ].join('\n');
 -->
 [![Gradle plugin](https://img.shields.io/badge/plugins.gradle.org-com.diffplug.gradle.spotless-blue.svg)](https://plugins.gradle.org/plugin/com.diffplug.gradle.spotless)
-[![Maven central](https://img.shields.io/badge/mavencentral-com.diffplug.gradle.spotless%3Aspotless-blue.svg)](http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-plugin-gradle%22)
+[![Maven central](https://img.shields.io/badge/mavencentral-com.diffplug.gradle.spotless%3Aspotless-blue.svg)](https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-plugin-gradle%22)
 [![Javadoc](https://img.shields.io/badge/javadoc-3.18.0-blue.svg)](https://diffplug.github.io/spotless/javadoc/spotless-plugin-gradle/3.18.0/)
 
 [![Changelog](https://img.shields.io/badge/changelog-3.19.0--SNAPSHOT-brightgreen.svg)](CHANGES.md)
diff --git a/plugin-maven/README.md b/plugin-maven/README.md
index 220c943686..24354e2ede 100644
--- a/plugin-maven/README.md
+++ b/plugin-maven/README.md
@@ -2,7 +2,7 @@
 
 <!---freshmark shields
 output = [
-  link(shield('Maven central', 'mavencentral', '{{group}}:{{artifactIdMaven}}', 'blue'), 'http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22{{group}}%22%20AND%20a%3A%22{{artifactIdMaven}}%22'),
+  link(shield('Maven central', 'mavencentral', '{{group}}:{{artifactIdMaven}}', 'blue'), 'https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22{{group}}%22%20AND%20a%3A%22{{artifactIdMaven}}%22'),
   link(shield('Javadoc', 'javadoc', '{{stableMaven}}', 'blue'), 'https://{{org}}.github.io/{{name}}/javadoc/{{artifactIdMaven}}/{{stableMaven}}/'),
   '',
   link(shield('Changelog', 'changelog', '{{stableMaven}}', 'brightgreen'), 'CHANGES.md'),
@@ -11,7 +11,7 @@ output = [
   link(shield('License Apache', 'license', 'apache', 'brightgreen'), 'https://tldrlegal.com/license/apache-license-2.0-(apache-2.0)')
   ].join('\n');
 -->
-[![Maven central](https://img.shields.io/badge/mavencentral-com.diffplug.spotless%3Aspotless--maven--plugin-blue.svg)](http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-maven-plugin%22)
+[![Maven central](https://img.shields.io/badge/mavencentral-com.diffplug.spotless%3Aspotless--maven--plugin-blue.svg)](https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-maven-plugin%22)
 [![Javadoc](https://img.shields.io/badge/javadoc-1.18.0-blue.svg)](https://diffplug.github.io/spotless/javadoc/spotless-maven-plugin/1.18.0/)
 
 [![Changelog](https://img.shields.io/badge/changelog-1.18.0-brightgreen.svg)](CHANGES.md)
@@ -52,7 +52,7 @@ cmd> mvn spotless:check
 ...
 ```
 
-To use it in your pom, just [add the Spotless dependency](http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-maven-plugin%22), and configure it like so:
+To use it in your pom, just [add the Spotless dependency](https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.diffplug.spotless%22%20AND%20a%3A%22spotless-maven-plugin%22), and configure it like so:
 
 ```xml
 <plugin>
diff --git a/plugin-maven/build.gradle b/plugin-maven/build.gradle
index 0be27cfdf4..d95d429d43 100644
--- a/plugin-maven/build.gradle
+++ b/plugin-maven/build.gradle
@@ -15,7 +15,7 @@ visteg {
 	nodeShape = 'box'
 	startNodeShape = 'box'
 	endNodeShape = 'box'
-	colorscheme = 'pastel24' // http://www.graphviz.org/doc/info/colors.html
+	colorscheme = 'pastel24' // https://www.graphviz.org/doc/info/colors.html
 }
 
 import com.github.mustachejava.DefaultMustacheFactory