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Start your free trialVaibhav Yaramwar
Courses Plus Student 4,292 PointsWhat if two Implementation of Interfaces are there?
As Chris said in Service we are using Interface instated of Implementation and Spring will find Implementation of this Interface.
What if there are more than one Implementation of Interfaces ,in this case how spring will derive Implementation?
3 Answers
Daniel Vargas
29,184 PointsI'm not sure if you should implement more than once a DAO interface, however if that's the case you could just instantiate the implementation instead of the interface.
Andrey Serebryanskiy
5,756 PointsHere is the link from previous video's teacher's notes.
There is a precise answer to your question: if you have two or more implementations of an autowired interface you can use @Qulifier("RightImplClassName") annotation. For example:
public Example {
@Autowired
@Qualifier("SomeInterfaceImpl2")
private SomeInterface someInteface;
}
Boban Talevski
24,793 PointsIf you have two implementations, Spring will throw an exception, so you need to make sure you only have one. Check the teacher's notes in this previous video.
On a side note, you could have more than one implementation of an interface, but Spring will search for annotations on a class implementing that interface, so if only one class is annotated, you should still be ok and that's the class implementation which will be used for Autowiring.