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Notes of the Java developer

Java 8

Lambda functions

1. Method reference is another way of creating anonymous methods. Basically, what is does is - it creates implicit lambda function that invokes the specified method underneath. For example,

    Stream.of(1.5, 2.1, 3.2).map(Double::intValue).collect(Collectors.toList());

   is the shorthand of

   Stream.of(1.5, 2.1, 3.2).map(d -> d.intValue()).collect(Collectors.toList());

2. There are 4 types of method reference:
   1. Instance method reference. Reference to parameter object's method
   2. Other object's method reference. Reference to another instance's method. For example, System.out::println
   3. Static method reference. For example, Arrays::asList
   4. Constructor reference. Used to create new object using no-arg constructor. For example, HashMap::new