Functional Interface method can be mapped to our specified method by using :: (double colon) operator. This is called method reference.
Our
specified method can be either static method or instance
method.
Functional Interface method and our specified method should have same argument
types, except this the remaining things like return type, method name,
modifiers etc. are not required to match.
Syntax:
Case1:
If our specified method is static method
classname::methodName
Case2:
If the method name is instance method
objRef::methodName
Functional Interface can refer lambda expression and
Functional Interface can also refer method reference.
Hence lambda expression can be replace with method reference.
Hence method reference is alternative syntax to lambda expression.
