Java 8 Methods Reference (method references)

1 What is a method reference (methods references)

Java 8 adds a familiar but unfamiliar symbol::. You might see this code.

System.out::p rintln

is actually a method reference (methods references). Since Java 8 also takes the method/function as the first input parameter. So you will see Inventory.comparing (apple::getweight); This "strange" code.

2 How to use method references (methods references)

In fact, a method reference is a syntactic sugar of a lambda expression. It is possible to simplify the code by means of a method reference when the lambda refers to only one method references.

(Apple a), a.getweight () = = = Apple::getweight (), Thread.CurrentThread (). DumpStack () = = = Thread.CurrentThread ( )::d umpstack (str, i), str.substring (i) = = = String::substring (String s), System.out.println (s) = = = System.out:: println

3 Types of method references

3.1

static method Reference

Example: Integer::p arseint (Parsetint is a static method)

3.2

Instance method

Example: String::length (Length () is an instance method)

3.3

Instance Object method Reference

Example:

Person p = new person

P::getname (P is an instance object)

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Java 8 Methods Reference (method references)