Java中的类型擦除

// Here, T is bounded by Object i.e. java.lang.Object
class GFG<T> {
// Here, T will be replaced by default i.e. Object
    T obj; 
    GFG(T o)
    {
        obj = o;
    }
    T getob()
    {
        return obj;
    }
}


class GFG
{
// Here, T will be replaced by default i.e. Object
Object obj;
GFG(Object o)
{
obj=o;
}
Object getob()
{
return obj;
}
}


// Here, T is bounded by Object i.e. java.lang.Object
class Geeks<T extends String> {
 // Here, T will be replaced by String i.e. java.lang.String
    T str;
    Geeks(T o)
    {
        str = o;
    }
    T getob()
    {
        return str;
    }
}


class Geeks
{
//Here, T will be replaced by String i.e. java.lang.String
String str;
Geeks(String o)
{
str=o;
}
String getob()
{
return str;
}
}


// Java program to illustrate
// concept of TypeErasure
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class GenericsErasure {
    public static void main(String args[])
    {
        List<String> list = new ArrayList<String>();
        list.add("Hello");
        Iterator<String> iter = list.iterator();
        while (iter.hasNext()) {
            String s = iter.next();
            System.out.println(s);
        }
    }
}


// Java program to illustrate
// concept of TypeErasure
import java.io.PrintStream;
import java.util.*;
public class GenericsErasure {
    public GenericsErasure()
    {
    }
    public static void main(String args[])
    {
        List list = new ArrayList();
        list.add("Hello");
        String s;
        for (Iterator iter = list.iterator(); iter.hasNext();
             System.out.println(s))
            s = (String)iter.next();
    }
}