Qualifier

In cases where there could be an ambiguity in identifying an entity, qualifiers serve as the distinguishing factor to uniquely and unambiguously identify an entity.

Qualifiers are also identifers, which help remove ambiguity. But not all identifiers are qualifiers.

In addition to being used, where its not possible to interpret identifiers unambiguiosly, qualifiers can be used to --

1. Override a default context: If the default context is the current class or default database, qualifier can be used to override that.
2. Provide missing context: We can explicitly state the default context too to clearly indicate the intended context.

References

• Joop Eggen's comment on 'What does "qualified this" construct mean in java?' - StackOverflow
• Spring @Qualifier annotation - Baeldung
• Database Object Names and Qualifiers - Oracle Database

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Backlinks

• Qualified Identifier (cs)
• Unqualified Identifier (cs)
• Object Context Qualifiers (cs)
• Qualified this construct (cs)