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String Óë StringBufferÇø±ð:
String×Ö·û´®¶ÔÏóÊDz»¿É±äµÄ£»StringBufferÊDZ䳤ºÍ¿ÉдµÄ¶¯Ì¬×Ö·ûÐòÁУ¬¿ÉÒÔ×Ô¶¯µØÔö¼Ó¿Õ¼ä¡£
Integer var = new Integer();//ÓÐÓï·¨´íÎó
Integer var = new Integer(2);//悦﵀
javaµÄVector³ÉÔ±ÊÇÒªÓÃelementAt(i)³ÉÔ±º¯ÊýÀ´»ñµÃµÄ£¬²»ÄÜÓÃve[i]µÃµ½¡£
Vector::public Enumeration<E> elements() ·µ»Ø´ËÏòÁ¿µÄ×é¼þµÄö¾Ù¡£
Vector v = new Vector();
  v.add("aaaaaaaa");
  v.add("bbbbbbbbbbbb");
  for (Enumeration e = v.elements(); e.hasMoreElements();)
  {
   System.out.println(e.nextElement());
  }
//Êä³ö
//aaaaaaaa
//bbbbbbbbbbbb
½Ó¿ÚµÄʵÏÖ£ºFilenameFilterÊǽӿÚ
String[] names=f.list(new FilenameFilter()//µÃµ½ÒÔÉÏÎļþ¼ÐÏÂËùÓеÄÎļþÃûºÍĿ¼Ãû,´æ´¢ÔÚnamesÊý×éÖÐ
  {
   public boolean accept(File dir,String name)
   {
    return name.indexOf(".java")!=-1;
   }
  });
getClass().getName();
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javaËæ»úÊýµÄ²úÉú

1. import java.util.*; 
2.(A) public class Test
       { public static void main(String[] args)
         { 
         //Éú³É [0-n) ¸ö²»Öظ´µÄËæ»úÊý  st ÓÃÀ´±£´æ ......

JVMÏê½âÖ®JavaÀ¬»ø»ØÊÕ»úÖÆÏê½âºÍµ÷ÓÅ £¨3£©

 5.ÈçºÎ´ÓJVMÖлñÈ¡ÐÅÏ¢À´½øÐе÷Õû
¡¡¡¡-verbose.gc¿ª¹Ø¿ÉÏÔʾgcµÄ²Ù×÷ÄÚÈÝ¡£´ò¿ªËü£¬¿ÉÒÔÏÔʾ×îæºÍ×î¿ÕÏÐÊÕ¼¯ÐÐΪ·¢ÉúµÄʱ¼ä¡¢ÊÕ¼¯Ç°ºóµÄÄÚ´æ´óС¡¢ÊÕ¼¯ÐèÒªµÄʱ¼äµÈ¡£´ò¿ª- xx:+ printgcdetails¿ª¹Ø£¬¿ÉÒÔÏêϸÁ˽âgcÖеı仯¡£´ò¿ª-XX: + PrintGCTimeStamps¿ª¹Ø£¬¿ÉÒÔÁ˽âÕâЩÀ¬»øÊÕ¼¯·¢ÉúµÄʱ¼ä£¬×ÔjvmÆô¶¯ÒÔºóÒÔ ......

*³ÉΪJava¸ßÊÖµÄ25¸öѧϰҪµã*

 1. ÄãÐèÒª¾«Í¨ÃæÏò¶ÔÏó·ÖÎöÓëÉè¼Æ£¨OOAOOD£©¡¢É漰ģʽ£¨GOF£¬J2EEDP£©ÒÔ¼°×ÛºÏģʽ¡£ÄãÓ¦¸ÃÁ˽âUML£¬ÓÈÆäÊÇclass¡¢object¡¢interactionÒÔ¼°statediagrams. ¡¡¡¡2. ÄãÐèҪѧϰJavaÓïÑԵĻù´¡ÖªÊ¶ÒÔ¼°ËüµÄºËÐÄÀà¿â£¨collections¡¢serialization¡¢streams¡¢networking¡¢multithreading¡¢reflection¡¢event¡¢handling¡¢N ......

Execlµ¼Èënotes JAVA´úÀí

 import lotus.domino.*;
import java.io.*;
import java.util.Vector;
import jxl.*;
/*******************************************************************************
 * @saveSQMessageToOracle
 * @×÷ÕߣºÐ컪Ïé
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 * @˵Ã÷£ºExeclÎļþµÄµ¼Èë
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javaÎļþ·ÃÎÊFileÀ༰Æä¹ýÂË

import java.io.*;
class FileTest
{
 public static void main(String[] args) throws Exception
 {
  //File f=new File("1.txt");
  //f.createNewFile();
  //f.mkdir();
  //File f=new File("E:\\JavaLesson\\Lesson7\\1.txt");//ÔÚWindowsϵͳÏÂ,Óþø¶Ô ......
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