Java:: Double colon operator in Java

Source: Internet
Author: User

The double colon operator definition in Java

The double-colon operator is a handle to a class method, a shorthand for a lambda expression called eta-conversion or η-conversion.

The usual case:

Simplify X-System.out.println (x) to System.out: The process of:p Rintln is called eta-conversion

The process of simplifying System.out::p rintln to X, System.out.println (x) is called Eta-expansion

Class Name:: Method Name


    1. method is not followed by ()
    2. Lazy Load method is called to see caller usage
Using the example method call

Person--person.getage ();
Can replace

X-System.out.println (x)
Can replace
System.out::p rintln
Out is an object of the PrintStream class, and println is the method of the class that overloads the method based on the type of X

Creating objects

(), New arraylist<> ();
can be replaced by
The New keyword actually calls the construction method of the ArrayList

JVM implementation

The JVM's underlying implementation is callsite, and the interface to the JDK layer burst is functional


Java:: Double colon operator in Java

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