以下網址是他人的總結， 值得我們學習！  感謝這些人的技術總結！

 為什麼引入泛型：

ｊａｖａ　深入學習

JVM原理：

Java類載入器：

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package package1;

public class testObject {

 public static void main(String[] args) {
   
     int a = 1;       
        int b = 1;
       
        boolean b0 = true;
        boolean b1 = false;
       
        System.out.println("測試：a==b:"+(a==b));    
        System.out.println("測試：b0==b1:"+(b0==b1));    
 }
}

輸出結果：

測試：a==b:true
測試：b0==b1:false

============================================

package package1;

public class testObject {

 public static void main(String[] args) {
      
  testObject to1 = new testObject();
  
  testObject to2 = new testObject();
  
     System.out.println(("to1==to2:")+(to1==to2));            
 }
}

輸出結果：

to1==to2:false

解析：物件的記憶體首地址不同。

======================

package package1;

public class testObject {

 public static void main(String[] args) {
      
  testObject to1 = new testObject();
    
     System.out.println( "to1:" + to1 );  

  
     System.out.println( "to1.toString():" + to1.toString() );  
    
    
 }
}

輸出結果：

to1:[email protected]
to1.toString():[email protected]

===================================================

package package1;

public class testObject {

 String name;
 
 
 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public String toString(){  
  return "object name is:"+ name ;
 }

 public static void main(String[] args) {
      
  testObject to1 = new testObject();
  
  to1.setName("China");
    
     System.out.println( "to1:" + to1 );  
           
 }
}

輸出結果：

to1:object name is:China
============================================

package package1;

public class testObject {

 public static void main(String[] args) {
      
     String s0 = "HelloChina";
       
        String s1 = new String("HelloChina");       

        System.out.println("s0==s1:" + ( s0 == s1 ));

 }
}

輸出結果：

s0==s1:false

====================================================================

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Ｊａｖａ大牛：

http://coolshell.cn/ 陳皓的部落格
http://blog.nosqlfan.com/ nosql的部落格
http://ifeve.com/ java併發程式設計的

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HashMap

package com;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class hashMapDemo {

 public static void main(String[] args) {

      HashMap hm = new HashMap();
     
      hm.put("john", new Integer(96) );
     
      hm.put("tom", new Integer(98) );
     
      hm.put("magang", new Integer(100) );
     
   System.out.println( "john is now balance:"+hm.get("john")  );

      Set set = hm.entrySet();
     
      Iterator i = set.iterator();
     
      while( i.hasNext() )
      {
       Map.Entry me = ( Map.Entry ) i.next();
       System.out.print( me.getKey() +":" );
       System.out.println( me.getValue()  );

      }
     
      int balance = ( ( Integer) hm.get("john")).intValue();
      hm.put("john", new Integer((int)(balance+1200)));
     
   System.out.println( "john is new balance:"+hm.get("john")  );

 }

}  

輸出結果：

john is now balance:96
magang:100
tom:98
john:96
john is new balance:1296

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