Learn the lambda essay on the Java Core Technology volume

Lambda An expression

form: parameter, arrow (-), expression

Parameter type to write, if you can deduce it can not write

Only one argument can omit parentheses

No arguments to write empty brackets ()

* If the branch returns a value, then all branches will return a value, otherwise it is illegal

function interface: interface with only one abstract method (can be marked with @functionalinterface annotations)

For example, you can do this in Javax.swing.Timer.

　　　　　　Timer T = new timer (+, event-

{

...

});

The second parameter of this constructor requires a ActionListener instance, ActionListener

is an interface that has only one method, so you can use a lambda expression.

Method reference

Object::instancemethod

Class::staticmethod

Class::instancemethod

Such as: Event-System.out.println (event) is equivalent to System.out:: println

Math::p ow equivalent to (x, y)-Math.pow (x, y)

In the third case, the first parameter becomes the target of the method, such as: String::comparetoignorecase equivalent to (x, y), X.comparetoignorecase (y)

There is also the ability to use this and super parameters;

Super:: Instancemethod

Constructor Reference:

X-New int[x] equivalent to Int[]::new

Person x = New person (...) equivalent to Person::new

When there are multiple constructors, the compiler infers from the context

Learn the lambda essay on the Java Core Technology volume