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Java 8 - Functions - Anonymous Function



  • Anonymous function (or Lambda) is a function without a reference variable.
  • We use Lambdas when there is no need to store a reference to a function object, e.g. when passing a function as input parameter to a method or implementing a functional interface.

printer method which accepts a function
void printer(String input, Consumer<String> stringConsumer) {
   stringConsumer.accept(input);
}

string to integer converter method
Integer stringToIntegerConverter(String input, Converter<String, Integer> converter) {
   return converter.convert(input);
}


functional interface with name Converter
@FunctionalInterface
interface Converter<F, T> {
   T convert(F from);
}


USAGE

 passing an anonymous function as input parameter to printer method 
printer("Tom", i -> log.info("Hello " + i));

 implementing a functional interface using anonymous function
log.info("stringToIntegerConverter output: " + stringToIntegerConverter("1", i -> Integer.valueOf(i)));
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