ダークホースプログラマー_Javaハイテク_その三_汎用型

public class GenericTest {
	public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException {
		// TODO Auto-generated method stub
        /*  ArrayList collection1=new ArrayList();
          collection1.add(1);
          collection1.add(1L);
          collection1.add("abc");
          int i=(Integer)collection1.get(1); */
          ArrayList<String>  collection2=new ArrayList();
         // collection2.add(1);
          //collection2.add(1L);
          collection2.add("abc");
          String str=collection2.get(0); 
          Constructor constructor1=String.class.getConstructor((StringBuffer.class));
      	String str2=(String) constructor1.newInstance(new StringBuffer("abc"));//            
      	System.out.println(str2); 
      	ArrayList<Integer> collection3=new ArrayList();
      	System.out.println(collection3.getClass()==collection2.getClass());
      	//collection3.add("abc");  
      	collection3.getClass().getMethod("add", Object.class).invoke(collection3, "abc");
      	System.out.println(collection3.get(0)); 
         
           printCollection(collection3);
           
           
           HashMap<String,Integer> maps=new HashMap<String,Integer>();
           maps.put("zxx",28);
           maps.put("lhm",35);
           maps.put("flx",33);
           Set<Map.Entry<String,Integer>> entrySet=maps.entrySet();
           for(Map.Entry<String,Integer> entry:entrySet){
          	 System.out.println(entry.getKey()+":"+entry.getValue());
           }
          	 add(3,5);
          	 Number x1=add(3.5,3);
          	 Object str6=add(3,"abc");
          	 swap(new String[]{"abc","xyz","itcast"},1,2);
          	 //swap(new int[]{1,3,5,4,5),3,4};          
          	 
          	 
        		   
	}
     public static void printCollection(Collection<?> collection){
    	 //collection.add("abc");
    	 System.out.println(collection.size());
    	 for(Object obj:collection){
    		 System.out.println(obj); 
    	 }
     }
     //Class<Number> x=String.class.asSubclass(Number.class);
     //Class<?> y;
     //Class<String> x;//Class.forName("java.lang.String");
      //y=x;
    public static <T> void swap(T[] a,int i,int j){
    	T tmp=a[i];
    	a[i]=a[j];
    	a[j]=tmp;
    }
      
     private static <T> T  add(T x,T y){
    	  return null;
      }
}