l          陣列：  宣告l           一維陣列宣告：n           int a1[] = new int[5];n           int[] a1;  a1 = new int[5];  // 但不可以int[5] a1((宣告陣列大小只能在”=”右邊)n           int testArray[]; testAr

l          Garbage Collection：l           讓物件能”有機會”被garbage collected的方法：n           nulling a referencen           reassigning a reference valuen           isolating a referencel          

l          Utility Classesl           class、method、constructor、Boolean、...都是object。l           System Properties(系統參數)用途取出或設定系統參數舉例java –Deigh=8 Testprintln(System.getPro

1.Given the following1.class MyThread extends Thread {2.    3.    public static void main(String []args){4.       MyThread t = new MyThread();5.        t.run();6.           }7.8.        public void ru

在javaworld.com.tw上看到的一个SCJPER的学习总结，不错，直接COPY过来用了；Chapter 1:1.1 分辨keywords, 以及記得Java所擁有的Reserve Words1.2 所有primitive data type的range, 以及他們的default value1.3 如何声明一個array. (注意anonymous array的部分, 少見) 1.4 所

l          The Collection Frameworkl           特性表  有順序可重覆Thread safe排序ListVectorYesYesNoStackLinkedListNoArrayList Se

20.Given the following.public class SyncTestInner{     public static void main(String[] args) {          Thread t = new Thread(){           Foo f = new Foo();{            f.increase(20);              

11.Which three are methods of the Object class?(Choose three.)A.    notify();B.    notifyAll();C.    isInterrupted();D.    synchronized();E.    interrupt();F.    wait(long msecs);G.    sleep(long msec

Example:    Class Teacher and Student are subclass of class Person.    Person p;    Teacher t;    Student s;    p, t and s are all non-null.    if(t instanceof Person) {  s = (Student)t; }

l          Polymorphism 1.  class A{2.    int x = 1;3.    int y = 2;4.    int f() { return x; }5.    static char sf() { return ‘A’; }6.  }7.  class B extend A{8.    int x = 3;  // sh

目的l           當發生錯誤或執行到一個throw statement，馬上停止正常的程式執行，去尋找適當的exception handler來處理throw statement所丟出的意外狀況。分類l           可以用在throw statement的：Error、Throwable、Exception、RuntimeExcepti