I study This tutorial . In some screenshots, there is a - & gt; , for example:
vertx.deployverticle ("com.mycompany.myrderprocessortellic", res - & gt; {
if (res.Succeeded ()) {
System.Out.printLN ("Deployment ID IS:" + Res.Result ());
} else {
System.Out.printLN ("Deployment Failed!");
}
});
did not come across before with such. Tell me, please, what is it and where you can read good materials about it.
Answer 1, Authority 100%
This is a lambda expression – an anonymous function. Simply put, this is the method without an ad (without access modifiers that return value and name) .
appeared in the 8 version of Java.
Example of use
Write a simple example function interface :
Public Interface Lambda {
// Interface Method with Missing Implementation
int getDoubleValue (int val);
// Interface Method with default implementation
Default Void Printval (Int Val) {
System.out.printLN (VAL);
}
}
The function interface must have only one abstract method. You can read about the reasons for such a limitation here .
Now create a class for use
Public Class ClassForlambda {
Public Static Void Main (String [] Args) {
// declare a link to the function interface
Lambda lam;
// Parameter for our abstract method
int num = 9;
// prescribate the first implementation option
LAM = (VAL) - & gt; Val * 2;
System.out.PrintLN (LAM.GETDOUBLEVALUE (NUM));
// We prescribe a second embodiment
LAM = (VAL) - & gt; {
System.Out.printLN ("Your Number IS" + Val);
Return Val * 2;
};
System.out.PrintLN (LAM.GETDOUBLEVALUE (NUM));
}
}
As you can see, the appeal to the method has not changed. Only implementation was subjected to change.