Support for java.util.Optional with @Inject (a la @Autowired's required=false) [SPR-11833]

[spring-projects-issues]

Juergen Hoeller opened SPR-11833 and commented

Java 8's java.util.Optional is a new common type to mark references as non-required. It'd be nice to support this with @Inject at the injection point level, as an alternative to @Autowired's required=false attribute.

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Issue Links:

• Support for java.util.Optional as a @RequestParam [SPR-11829] #16448 Support for java.util.Optional as a @RequestParam
• Support @Nullable annotations as indicators for optional injection points [SPR-15028] #19595 Support @Nullable annotations as indicators for optional injection points
• Allow autowiring of empty collection in @Bean method parameters using java.util.Optional [SPR-9132] #13771 Allow autowiring of empty collection in @Bean method parameters using java.util.Optional
• Data binding with java.util.Optional: traversal of nested paths, detection of empty holders [SPR-12241] #16855 Data binding with java.util.Optional: traversal of nested paths, detection of empty holders

Referenced from: commits 5cb3f8e, 7d03daf