Fix links in Javadoc and reference docs

- Fix broken links (by using a new URL, an alternative URL, or a
  Wayback Machine link)

- Use HTTPS where possible

- Remove https://issuetracker.springsource.com/browse/EBR-349: this
  link is dead and is also mentioned in
  https://jira.spring.io/browse/SPR-8093

- Clean up nohttp allowlist.lines

Closes gh-28876

src/docs/asciidoc/core/core-expressions.adoc

@@ -1677,7 +1677,7 @@ ternary operator.
 === The Elvis Operator
 
 The Elvis operator is a shortening of the ternary operator syntax and is used in the
-http://www.groovy-lang.org/operators.html#_elvis_operator[Groovy] language.
+https://www.groovy-lang.org/operators.html#_elvis_operator[Groovy] language.
 With the ternary operator syntax, you usually have to repeat a variable twice, as the
 following example shows:
 
@@ -1756,7 +1756,7 @@ This will inject a system property `pop3.port` if it is defined or 25 if not.
 === Safe Navigation Operator
 
 The safe navigation operator is used to avoid a `NullPointerException` and comes from
-the http://www.groovy-lang.org/operators.html#_safe_navigation_operator[Groovy]
+the https://www.groovy-lang.org/operators.html#_safe_navigation_operator[Groovy]
 language. Typically, when you have a reference to an object, you might need to verify that
 it is not null before accessing methods or properties of the object. To avoid this, the
 safe navigation operator returns null instead of throwing an exception. The following

src/docs/asciidoc/data-access.adoc

@@ -131,7 +131,7 @@ Typically, you need an application server's JTA capability only if your applicat
 to handle transactions across multiple resources, which is not a requirement for many
 applications. Many high-end applications use a single, highly scalable database (such as
 Oracle RAC) instead. Stand-alone transaction managers (such as
-https://www.atomikos.com/[Atomikos Transactions] and http://jotm.objectweb.org/[JOTM])
+https://www.atomikos.com/[Atomikos Transactions] and https://jotm.ow2.org/[JOTM])
 are other options. Of course, you may need other application server capabilities, such as
 Java Message Service (JMS) and Java EE Connector Architecture (JCA).
 
@@ -2875,7 +2875,7 @@ treats them as errors.
 
 For more information about the Spring Framework's transaction support, see:
 
-* https://www.javaworld.com/javaworld/jw-01-2009/jw-01-spring-transactions.html[Distributed
+* https://www.infoworld.com/article/2077963/distributed-transactions-in-spring--with-and-without-xa.html[Distributed
   transactions in Spring, with and without XA] is a JavaWorld presentation in which
   Spring's David Syer guides you through seven patterns for distributed
   transactions in Spring applications, three of them with XA and four without.
@@ -6224,7 +6224,7 @@ it with values from the Java `ARRAY`, as the following example shows:
 === Embedded Database Support
 
 The `org.springframework.jdbc.datasource.embedded` package provides support for embedded
-Java database engines. Support for http://www.hsqldb.org[HSQL],
+Java database engines. Support for https://www.hsqldb.org[HSQL],
 https://www.h2database.com[H2], and https://db.apache.org/derby[Derby] is provided
 natively. You can also use an extensible API to plug in new embedded database types and
 `DataSource` implementations.

src/docs/asciidoc/rsocket.adoc

@@ -53,7 +53,7 @@ through RSocket across the network.
 === The Protocol
 
 One of the benefits of RSocket is that it has well defined behavior on the wire and an
-easy to read https://rsocket.io/about/Protocol[specification] along with some protocol
+easy to read https://rsocket.io/about/protocol[specification] along with some protocol
 {gh-rsocket}/rsocket/tree/master/Extensions[extensions]. Therefore it is
 a good idea to read the spec, independent of language implementations and higher level
 framework APIs. This section provides a succinct overview to establish some context.

src/docs/asciidoc/testing.adoc

@@ -92,7 +92,7 @@ parties such as https://github.com/h-thurow/Simple-JNDI[Simple-JNDI].
 The `org.springframework.mock.web` package contains a comprehensive set of Servlet API
 mock objects that are useful for testing web contexts, controllers, and filters. These
 mock objects are targeted at usage with Spring's Web MVC framework and are generally more
-convenient to use than dynamic mock objects (such as http://easymock.org/[EasyMock])
+convenient to use than dynamic mock objects (such as https://easymock.org/[EasyMock])
 or alternative Servlet API mock objects (such as http://www.mockobjects.com[MockObjects]).
 
 TIP: Since Spring Framework 5.0, the mock objects in `org.springframework.mock.web` are
@@ -7729,13 +7729,13 @@ WebTestClient]. Browse these examples for further ideas.
 ==== HtmlUnit Integration
 
 Spring provides integration between <<spring-mvc-test-server, MockMvc>> and
-http://htmlunit.sourceforge.net/[HtmlUnit]. This simplifies performing end-to-end testing
+https://htmlunit.sourceforge.io/[HtmlUnit]. This simplifies performing end-to-end testing
 when using HTML-based views. This integration lets you:
 
 * Easily test HTML pages by using tools such as
-  http://htmlunit.sourceforge.net/[HtmlUnit],
+  https://htmlunit.sourceforge.io/[HtmlUnit],
   https://www.seleniumhq.org[WebDriver], and
-  http://www.gebish.org/manual/current/#spock-junit-testng[Geb] without the need to
+  https://www.gebish.org/manual/current/#spock-junit-testng[Geb] without the need to
   deploy to a Servlet container.
 * Test JavaScript within pages.
 * Optionally, test using mock services to speed up testing.
@@ -8062,11 +8062,11 @@ First, we no longer have to explicitly verify our form and then create a request
 looks like the form. Instead, we request the form, fill it out, and submit it, thereby
 significantly reducing the overhead.
 
-Another important factor is that http://htmlunit.sourceforge.net/javascript.html[HtmlUnit
+Another important factor is that https://htmlunit.sourceforge.io/javascript.html[HtmlUnit
 uses the Mozilla Rhino engine] to evaluate JavaScript. This means that we can also test
 the behavior of JavaScript within our pages.
 
-See the http://htmlunit.sourceforge.net/gettingStarted.html[HtmlUnit documentation] for
+See the https://htmlunit.sourceforge.io/gettingStarted.html[HtmlUnit documentation] for
 additional information about using HtmlUnit.
 
 [[spring-mvc-test-server-htmlunit-mah-advanced-builder]]
@@ -8673,7 +8673,7 @@ TIP: For additional information on creating a `MockMvc` instance, see
 ===== MockMvc and Geb
 
 In the previous section, we saw how to use MockMvc with WebDriver. In this section, we
-use http://www.gebish.org/[Geb] to make our tests even Groovy-er.
+use https://www.gebish.org/[Geb] to make our tests even Groovy-er.
 
 [[spring-mvc-test-server-htmlunit-geb-why]]
 ====== Why Geb and MockMvc?
@@ -8776,7 +8776,7 @@ if we were at the wrong page.
 
 Next, we create a `content` closure that specifies all the areas of interest within the
 page. We can use a
-http://www.gebish.org/manual/current/#the-jquery-ish-navigator-api[jQuery-ish Navigator
+https://www.gebish.org/manual/current/#the-jquery-ish-navigator-api[jQuery-ish Navigator
 API] to select the content in which we are interested.
 
 Finally, we can verify that a new message was created successfully, as follows:
@@ -8793,7 +8793,7 @@ message == expectedMessage
 ----
 
 For further details on how to get the most out of Geb, see
-http://www.gebish.org/manual/current/[The Book of Geb] user's manual.
+https://www.gebish.org/manual/current/[The Book of Geb] user's manual.
 
 
 [[spring-mvc-test-client]]

src/docs/asciidoc/web/webflux-view.adoc

@@ -26,7 +26,7 @@ configuration involves a few bean declarations, such as
 `SpringResourceTemplateResolver`, `SpringWebFluxTemplateEngine`, and
 `ThymeleafReactiveViewResolver`. For more details, see
 https://www.thymeleaf.org/documentation.html[Thymeleaf+Spring] and the WebFlux integration
-http://forum.thymeleaf.org/Thymeleaf-3-0-8-JUST-PUBLISHED-td4030687.html[announcement].
+https://web.archive.org/web/20210623051330/http%3A//forum.thymeleaf.org/Thymeleaf-3-0-8-JUST-PUBLISHED-td4030687.html[announcement].
 
 
 

src/docs/asciidoc/web/webflux.adoc

@@ -34,7 +34,7 @@ The other part of the answer is functional programming. Much as the addition of
 in Java 5 created opportunities (such as annotated REST controllers or unit tests), the addition
 of lambda expressions in Java 8 created opportunities for functional APIs in Java.
 This is a boon for non-blocking applications and continuation-style APIs (as popularized
-by `CompletableFuture` and http://reactivex.io/[ReactiveX]) that allow declarative
+by `CompletableFuture` and https://reactivex.io/[ReactiveX]) that allow declarative
 composition of asynchronous logic. At the programming-model level, Java 8 enabled Spring
 WebFlux to offer functional web endpoints alongside annotated controllers.
 
@@ -87,7 +87,7 @@ Spring WebFlux. It provides the
 https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Mono.html[`Mono`] and
 https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Flux.html[`Flux`] API types
 to work on data sequences of 0..1 (`Mono`) and 0..N (`Flux`) through a rich set of operators aligned with the
-ReactiveX http://reactivex.io/documentation/operators.html[vocabulary of operators].
+ReactiveX https://reactivex.io/documentation/operators.html[vocabulary of operators].
 Reactor is a Reactive Streams library and, therefore, all of its operators support non-blocking back pressure.
 Reactor has a strong focus on server-side Java. It is developed in close collaboration
 with Spring.

src/docs/asciidoc/web/webmvc-view.adoc

@@ -479,7 +479,7 @@ In similar fashion, you can specify HTML escaping per field, as the following ex
 [[mvc-view-groovymarkup]]
 == Groovy Markup
 
-The http://groovy-lang.org/templating.html#_the_markuptemplateengine[Groovy Markup Template Engine]
+The https://groovy-lang.org/templating.html#_the_markuptemplateengine[Groovy Markup Template Engine]
 is primarily aimed at generating XML-like markup (XML, XHTML, HTML5, and others), but you can
 use it to generate any text-based content. The Spring Framework has a built-in
 integration for using Spring MVC with Groovy Markup.

src/docs/asciidoc/web/websocket.adoc

@@ -597,7 +597,7 @@ a key reason for having SockJS. This section covers important
 considerations about running in those browsers.
 
 The SockJS client supports Ajax/XHR streaming in IE 8 and 9 by using Microsoft's
-https://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx[`XDomainRequest`].
+https://web.archive.org/web/20160219230343/https://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx[`XDomainRequest`].
 That works across domains but does not support sending cookies.
 Cookies are often essential for Java applications.
 However, since the SockJS client can be used with many server