Fix Javadoc links to JSR 305 annotations

[ullenboom]

Take a look at https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/lang/NonNull.html:

@Target(value={METHOD,PARAMETER,FIELD})
@Retention(value=RUNTIME)
@Documented
@Nonnull
@TypeQualifierNickname
public @interface NonNull

The link behind Nonnull points to https://docs.oracle.com/javase/8/docs/api/javax/annotation/Nonnull.html?is-external=true, which is wrong

Nonnull is a JSR-305 datatype.

[sbrannen]

I attempted to address this by adding an explicit external Javadoc link URL to our Gradle build script for http://static.javadoc.io/com.google.code.findbugs/jsr305/3.0.2/, but that doesn't seem to help.

I assume that's because that site and the Java 8 Javadoc site both contain javax.annotation in their package-list files.

• https://www.javadoc.io/doc/com.google.code.findbugs/jsr305/3.0.2/package-list
• https://docs.oracle.com/javase/8/docs/api/package-list

I am not sure if the javadoc tool supports split packages across multiple external Javadoc sites, so there might not be a way to address this issue.

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Related thread on Twitter: https://twitter.com/sam_brannen/status/1482051231006789637

[sbrannen]

In a681d6a, I did the best that we can do to support Javadoc links to JSR 305 types; however, we cannot support @NonNull and other types in the javax.annotation (or jakarta.annotation) package due to the split package. See the commit message for details.