Use HTTPS for external links wherever possible

See gh-16316

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/CrshAutoConfiguration.java

@@ -105,7 +105,7 @@ import org.springframework.util.StringUtils;
  * context.
  * <p>
  * Additional shell commands can be implemented using the guide and documentation at
- * <a href="http://www.crashub.org">crashub.org</a>. By default Boot will search for
+ * <a href="https://www.crashub.org">crashub.org</a>. By default Boot will search for
  * commands using the following classpath scanning pattern {@code classpath*:/commands/**}
  * . To add different locations or override the default use
  * {@code shell.command_path_patterns} in your application configuration.

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/JolokiaAutoConfiguration.java

@@ -53,7 +53,7 @@ import org.springframework.web.servlet.mvc.ServletWrappingController;
  * <p>
  * Additional configuration parameters for Jolokia can be provided by specifying
  * {@code jolokia.config.*} properties. See the
- * <a href="http://jolokia.org">http://jolokia.org</a> web site for more information on
+ * <a href="https://jolokia.org">https://jolokia.org</a> web site for more information on
  * supported configuration parameters.
  *
  * @author Christian Dupuis

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/rich/RichGauge.java

@@ -24,7 +24,7 @@ import org.springframework.util.Assert;
  * The value of the average will depend on whether a weight ('alpha') is set for the
  * gauge. If it is unset, the average will contain a simple arithmetic mean. If a weight
  * is set, an exponential moving average will be calculated as defined in this
- * <a href="http://www.itl.nist.gov/div898/handbook/pmc/section4/pmc431.htm">NIST
+ * <a href="https://www.itl.nist.gov/div898/handbook/pmc/section4/pmc431.htm">NIST
  * document</a>.
  *
  * @author Luke Taylor

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/MetricFilterAutoConfigurationTests.java

@@ -390,7 +390,7 @@ public class MetricFilterAutoConfigurationTests {
 						throws ServletException, IOException {
 			// send redirect before filter chain is executed, like Spring Security sending
 			// us back to a login page
-			response.sendRedirect("http://example.com");
+			response.sendRedirect("https://example.com");
 		}
 
 	}