Use HTTPS links in documentation where possible

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

@@ -1093,7 +1093,7 @@ The `number` package provides `NumberStyleFormatter`, `CurrencyStyleFormatter`,
 `PercentStyleFormatter` to format `Number` objects that use a `java.text.NumberFormat`.
 The `datetime` package provides a `DateFormatter` to format `java.util.Date` objects with
 a `java.text.DateFormat`. The `datetime.joda` package provides comprehensive datetime
-formatting support based on the http://joda-time.sourceforge.net[Joda-Time library].
+formatting support based on the https://www.joda.org/joda-time/[Joda-Time library].
 
 The following `DateFormatter` is an example `Formatter` implementation:
 

src/docs/asciidoc/testing.adoc

@@ -6056,7 +6056,7 @@ See the following resources for more information about testing:
   using Java's proxy mechanism.`" Used by the Spring Framework in its test suite.
 * https://jmock.org/[JMock]: Library that supports test-driven development of Java
   code with mock objects.
-* http://dbunit.sourceforge.net/[DbUnit]: JUnit extension (also usable with Ant and
+* https://www.dbunit.org/[DbUnit]: JUnit extension (also usable with Ant and
   Maven) that is targeted at database-driven projects and, among other things, puts your
   database into a known state between test runs.
 * https://sourceforge.net/projects/grinder/[The Grinder]: Java load testing framework.