Shulou(Shulou.com)06/02 Report--

This article mainly introduces "Java generic instance analysis" related knowledge, Xiaobian through the actual case to show you the operation process, the operation method is simple and fast, practical, I hope this "Java generic instance analysis" article can help you solve the problem.

First, let's look at the classic usage of generic Java:

import java.util.*;

public class UseGeneric

{

public static void main(String[] args)

{

Vectorvi = new Vector();

vi.add(new Integer(24));

vi.add(35);

for(Integer i : vi)

{

System.out.println(i);

}

}

}

The code above demonstrates three new features: generic containers, autoboxing, and enhanced for loops. Indeed, from a code simplification perspective, these new features help--of course, autoboxing shouldn't really be a meaningful feature, just because Java's inherent two typing systems treat int, char, and other primitive types differently from objects, so autoboxing had to be used as a remedy when introducing generic containers.

Decompile the compiled class above to get the following code:

import java.io.PrintStream;

import java.util.Vector;

public class UseGeneric

{

public UseGeneric()

{

}

public static void main(String args[])

{

Vector vector = new Vector();

vector.add(new Integer(24));

vector.add(Integer.valueOf(35));

Integer integer;

for(SimpleIterator simpleiterator = vector.iterator(); simpleiterator.hasNext(); System.out.println(integer))

integer = (Integer)simpleiterator.next();

}

}

As you can see, all the new features are implemented on top of existing virtual machines, and there is nothing new about them. Indeed, as Joshua Bloch said, it was simply a matter of converting some code previously written by programmers into code written by compilers.

Then I tried to implement some slightly more advanced generic techniques, such as type traits. I wrote the following code:

// General Traits

class NumTraits

{

public void doSomething()

{

System.out.println("General Traits");

}

}

// Specialized Traits

class NumTraits

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.