@Testpublic void supplierWithOptional(){
Supplier<Double> doubleSupplier = () -> Math.random();
Optional<Double> optionalDouble = Optional.empty();
System.out.println(optionalDouble.orElseGet(doubleSupplier));}@Testpublic void whenNamesPresentUseBothConsumer(){
List<String> cities = Arrays.asList("Sydney", "Dhaka", "New York", "London");
Consumer<List<String>> upperCaseConsumer = list -> {
for(int i=0; i< list.size(); i++){
list.set(i, list.get(i).toUpperCase());
}
};
Consumer<List<String>> printConsumer = list -> list.stream().forEach(System.out::println);
upperCaseConsumer.andThen(printConsumer).accept(cities);}@Testpublic void whenNamesPresentUseBothConsumer(){
List<String> cities = Arrays.asList("Sydney", "Dhaka", "New York", "London");
Consumer<List<String>> upperCaseConsumer = list -> {
for(int i=0; i< list.size(); i++){
list.set(i, list.get(i).toUpperCase());
}
};
Consumer<List<String>> printConsumer = list -> list.stream().forEach(System.out::println);
upperCaseConsumer.andThen(printConsumer).accept(cities);}