Dark Horse programmer: Generic

---------------------Android Training,Java TrainingWe look forward to communicating with you!
---------------------

 

Generic: a special type that delays the operation of a specified type.CodeDeclare and instantiate classes or methods.
Generic Format: <data type>

Benefits of generics:
1: Solve the possible classcastexception problem during the runtime before the compilation.
2: the yellow line is removed and optimized.ProgramDesign.

3: You do not need to perform forced type conversion. Avoid type conversion exceptions.

Java generic parameters can only represent classes and cannot represent individual objects. Because the actual types of Java generic type parameters are eliminated during compilation, the type of the type parameters cannot be known at runtime. The Java compiler automatically adds the type conversion encoding when compiling generics, so the running speed will not be accelerated by the use of generics. Java allows constraints on some generic type parameters, including the following two forms (assuming T is a generic type parameter, c
Is a general class, generic class, or generic type parameter): T implements interface I. T is C, or inherits from C. A generic class cannot implement the throwable interface.

Example of generics:

 
Import Java. util. arraylist; import Java. util. iterator; public class genericdemo {public static void main (string [] ARGs) {arraylist <string> array = new arraylist <string> (); array. add ("Haha"); array. add ("hehe"); array. add ("Xixi"); // array. add (20); // here you have to add a clear data type to the iterator object. Iterator <string> it = array. iterator (); While (it. hasnext () {// string S = (string) it. next (); string S = it. next (); system. out. println (s);} system. out. println ("*****************"); // string [] strarray = new string [3]; // strarray [0] = "Haha"; // strarray [1] = "hehe"; // strarray [2] = 20 ;}}