易學筆記--從0開始學JAVA（個人純手工筆記共享免費！免費！免費！）--第5章初始化和清理

阿新 • • 發佈：2018-12-19

引數數量
引數型別

過載原則

//: HelloDate.java
import java.util.*;
//import static net.mindview.until.Print.*;
/** the first Thinking in java example program
  * display a string and today's date
  * @author wengyongsheng 
  * @version 4.0 
*/
public class HelloDate{
	/**
	* @param args array of string arguments
	*/
  public static void main(String []args) {
  System.out.println("Hello,It's: ");
  System.out.println(new Date());
//  print("Hello,It's: ");
}
}

class Tank{
	 int level;
}

class Assignment{
	public static void main(String []args) {
		Tank t1 = new Tank();
		Tank t2 = new Tank();
		t1.level = 9;
		t2.level = 47;
		System.out.println("1:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
    t1 = t2;
    System.out.println("2:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
		
		t1.level = 27;
		System.out.println("3:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);                   		                   
	}
}

class Letter{
	 char c;
}

class PassObject{
	static void f(Letter y){
		y.c = 'z';
	}
	public static void main(String []args) {
		Letter x = new Letter();
		System.out.println("1:x.c= " + x.c);
		x.c = 'a';
		System.out.println("2:x.c= " + x.c);
		f(x);
		System.out.println("3:x.c= " + x.c);
	}
}

class MathOps{
	public static void main(String []args) {
		Random rand = new Random(47);
		int i , j , k;
		j = rand.nextInt(100) + 1;
		System.out.println("j = " + j);
		k = rand.nextInt(100) + 1;
		System.out.println("k = " + k);
		i = j + k;
		System.out.println("i = " + i);
		
		float u , v , w;
		u = rand.nextFloat();
		System.out.println("u = " + u);
		v = rand.nextFloat() ;
		System.out.println("v = " + v);
		w = u + v;
		System.out.println("w = " + w);
	}
}

class AutoInc{
	public static void main(String []args) {
		int i = 1;
		System.out.println("i = " + i);
		System.out.println("++i = " + ++i);
		System.out.println("i++ = " + i++);
		System.out.println("i2 = " + i);
		System.out.println("--i = " + --i);
		System.out.println("i-- = " + i--);
		System.out.println("i3 = " + i);
 }
}
/* output
i = 1
++i = 2
i++ = 2
i2=3
--i = 2
i-- = 2
i3=1
*/

class Equaivalence{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1 == n2);
		System.out.println(n1 != n2);
 }
}

class EqualsMethod{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1.equals(n2));
 }
}

class Value{
	int i ;
}
class EqualsMethod2{
	public static void main(String []args) {
		Value v1 = new Value();
		Value v2 = new Value();
	 System.out.println(v1.equals(v2));
 }
}

class ShortCircuit{
	static boolean test1(int val){
		System.out.println("test1( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 1);
	}
	
	static boolean test2(int val){
		System.out.println("test2( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 2);
	}
	
	static boolean test3(int val){
		System.out.println("test3( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 3);
	}
	
	
	public static void main(String []args) {
		
		boolean b = test1(0) && test2(2) && test2(3);
		System.out.println("expression is : "  + b );
	}
}

class CommaOperator{
	public static void main(String []args) {
		for(int i = 1, j = i + 10; i < 5;i++,j = i*2){
			System.out.println("i =  "  +  i + " j = "  + j);
		}
 }
}


class ForEachFloat{
	public static void main(String []args) {
		Random rand = new Random(47);
		float f[] = new float[10];
		for(int i = 0; i < 10;i++){
			f[i] = rand.nextFloat();
		}
		
		for(float x:f){
			System.out.println("x =  " + x);
		}
		
		for(char c:"my name".toCharArray()){
			System.out.println("c =  " + c);
		}
 }
}

class LableedWhile{
	public static void main(String []args) {
		int i = 0;
		outer:
		while(true){
			System.out.println("Outer while loop");
			while(true){
				i++;
				System.out.println("i = " + i);
				if(i == 1){
					System.out.println("continue");
					continue;
				}
				if(i == 3){
					System.out.println("continue Outer");
					continue outer;
				}
				if(i == 5){
					System.out.println("break");
					break;
				}
				if(i == 7){
					System.out.println("break Outer");
					break outer;
				}
			}
		}
 }
}

class VoewlsAndConson{
	public static void main(String []args) {
		Random rand = new Random(47);
		for(int i = 0; i < 100;i++){
			int c = rand.nextInt(26) + 'a';
			System.out.println("c = " + c);
			switch(c){
				case 'a':
				case 'b':
				case 'c': System.out.println("vowel");break;
				case 'y':
				case 'w':
				case 'z':System.out.println("consonant");break;
				default:System.out.println("xxxx");
			}
		}
 }
}

class Flower{
	int petalCount = 0;
	String s = "init value";
	
	Flower(int peta){
		petalCount = peta;
		System.out.println("Flower(int peta)" );
	}
	
	Flower(String ss){
		s = ss;
		System.out.println("Flower(String ss) " );
	}
	
	
	Flower(String s,int patails){
		this(patails);
		this.s = s;
		System.out.println("Flower(String s,int patails) ");
	}
	
	Flower(){
		this("xxx",1);
		System.out.println("Flower() ");
	}
	public static void main(String []args) {
		Flower x = new Flower();
		
	}
}

輸出結果：

原始碼：

//: HelloDate.java
import java.util.*;
//import static net.mindview.until.Print.*;
/** the first Thinking in java example program
  * display a string and today's date
  * @author wengyongsheng 
  * @version 4.0 
*/
public class HelloDate{
	/**
	* @param args array of string arguments
	*/
  public static void main(String []args) {
  System.out.println("Hello,It's: ");
  System.out.println(new Date());
//  print("Hello,It's: ");
}
}

class Tank{
	 int level;
}

class Assignment{
	public static void main(String []args) {
		Tank t1 = new Tank();
		Tank t2 = new Tank();
		t1.level = 9;
		t2.level = 47;
		System.out.println("1:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
    t1 = t2;
    System.out.println("2:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
		
		t1.level = 27;
		System.out.println("3:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);                   		                   
	}
}

class Letter{
	 char c;
}

class PassObject{
	static void f(Letter y){
		y.c = 'z';
	}
	public static void main(String []args) {
		Letter x = new Letter();
		System.out.println("1:x.c= " + x.c);
		x.c = 'a';
		System.out.println("2:x.c= " + x.c);
		f(x);
		System.out.println("3:x.c= " + x.c);
	}
}

class MathOps{
	public static void main(String []args) {
		Random rand = new Random(47);
		int i , j , k;
		j = rand.nextInt(100) + 1;
		System.out.println("j = " + j);
		k = rand.nextInt(100) + 1;
		System.out.println("k = " + k);
		i = j + k;
		System.out.println("i = " + i);
		
		float u , v , w;
		u = rand.nextFloat();
		System.out.println("u = " + u);
		v = rand.nextFloat() ;
		System.out.println("v = " + v);
		w = u + v;
		System.out.println("w = " + w);
	}
}

class AutoInc{
	public static void main(String []args) {
		int i = 1;
		System.out.println("i = " + i);
		System.out.println("++i = " + ++i);
		System.out.println("i++ = " + i++);
		System.out.println("i2 = " + i);
		System.out.println("--i = " + --i);
		System.out.println("i-- = " + i--);
		System.out.println("i3 = " + i);
 }
}
/* output
i = 1
++i = 2
i++ = 2
i2=3
--i = 2
i-- = 2
i3=1
*/

class Equaivalence{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1 == n2);
		System.out.println(n1 != n2);
 }
}

class EqualsMethod{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1.equals(n2));
 }
}

class Value{
	int i ;
}
class EqualsMethod2{
	public static void main(String []args) {
		Value v1 = new Value();
		Value v2 = new Value();
	 System.out.println(v1.equals(v2));
 }
}

class ShortCircuit{
	static boolean test1(int val){
		System.out.println("test1( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 1);
	}
	
	static boolean test2(int val){
		System.out.println("test2( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 2);
	}
	
	static boolean test3(int val){
		System.out.println("test3( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 3);
	}
	
	
	public static void main(String []args) {
		
		boolean b = test1(0) && test2(2) && test2(3);
		System.out.println("expression is : "  + b );
	}
}

class CommaOperator{
	public static void main(String []args) {
		for(int i = 1, j = i + 10; i < 5;i++,j = i*2){
			System.out.println("i =  "  +  i + " j = "  + j);
		}
 }
}


class ForEachFloat{
	public static void main(String []args) {
		Random rand = new Random(47);
		float f[] = new float[10];
		for(int i = 0; i < 10;i++){
			f[i] = rand.nextFloat();
		}
		
		for(float x:f){
			System.out.println("x =  " + x);
		}
		
		for(char c:"my name".toCharArray()){
			System.out.println("c =  " + c);
		}
 }
}

class LableedWhile{
	public static void main(String []args) {
		int i = 0;
		outer:
		while(true){
			System.out.println("Outer while loop");
			while(true){
				i++;
				System.out.println("i = " + i);
				if(i == 1){
					System.out.println("continue");
					continue;
				}
				if(i == 3){
					System.out.println("continue Outer");
					continue outer;
				}
				if(i == 5){
					System.out.println("break");
					break;
				}
				if(i == 7){
					System.out.println("break Outer");
					break outer;
				}
			}
		}
 }
}

class VoewlsAndConson{
	public static void main(String []args) {
		Random rand = new Random(47);
		for(int i = 0; i < 100;i++){
			int c = rand.nextInt(26) + 'a';
			System.out.println("c = " + c);
			switch(c){
				case 'a':
				case 'b':
				case 'c': System.out.println("vowel");break;
				case 'y':
				case 'w':
				case 'z':System.out.println("consonant");break;
				default:System.out.println("xxxx");
			}
		}
 }
}

class Flower{
	int petalCount = 0;
	String s = "init value";
	
	Flower(int peta){
		petalCount = peta;
		System.out.println("Flower(int peta)" );
	}
	
	Flower(String ss){
		s = ss;
		System.out.println("Flower(String ss) " );
	}
	
	
	Flower(String s,int patails){
		this(patails);
		this.s = s;
		System.out.println("Flower(String s,int patails) ");
	}
	
	Flower(){
		this("xxx",1);
		System.out.println("Flower() ");
	}
	public static void main(String []args) {
		Flower x = new Flower();
		
	}
}


class Book{
 boolean checkedOut = false;
 Book(boolean checkedOut){
 	this.checkedOut = checkedOut;
 }
 void checkIn(){
 	checkedOut = false;
 }
 protected void finalize(){
 	if(checkedOut){
 		System.out.println(" protected void finalize：error ");
 	}
}
}

class Tcondition{
	public static void main(String []args) {
		Book novel = new Book(true);
		novel.checkIn();
		new Book(true);
		System.gc(); //進行強制終結動作
	}
}

輸出結果：

舉例：

靜態子句：

格式：
舉例：、

static宣告的物件，如果是在子句中，還是允許再次初始化

class StaticTests{

     public  int i = 0;

     

     public static StaticTest  staticTest1 = new StaticTest(400);

     public static StaticTest  staticTest2 = new StaticTest(500);

     {

           staticTest1 = new StaticTest(200);

           System.out.println("i="+i);

           

           staticTest2 = new StaticTest(300);

           System.out.println("i="+i);

           

     }

     

     static StaticTest staticTest = new StaticTest(100);

     

     StaticTests(){

           System.out.println("StaticTests初始化");

     }

     

     StaticTests(int i ){

           this.i = i;

           System.out.println("StaticTests初始化,i=" + i);

     }

     

     public static void main(String[] args) {

           StaticTests staticTest1 = new StaticTests();

           StaticTests staticTest2 = new StaticTests();

     }

}

陣列

舉例：

原始碼：

//: HelloDate.java
import java.util.*;
//import static net.mindview.until.Print.*;
/** the first Thinking in java example program
  * display a string and today's date
  * @author wengyongsheng 
  * @version 4.0 
*/
public class HelloDate{
	/**
	* @param args array of string arguments
	*/
  public static void main(String []args) {
  System.out.println("Hello,It's: ");
  System.out.println(new Date());
//  print("Hello,It's: ");
}
}

class Tank{
	 int level;
}

class Assignment{
	public static void main(String []args) {
		Tank t1 = new Tank();
		Tank t2 = new Tank();
		t1.level = 9;
		t2.level = 47;
		System.out.println("1:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
    t1 = t2;
    System.out.println("2:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
		
		t1.level = 27;
		System.out.println("3:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);                   		                   
	}
}

class Letter{
	 char c;
}

class PassObject{
	static void f(Letter y){
		y.c = 'z';
	}
	public static void main(String []args) {
		Letter x = new Letter();
		System.out.println("1:x.c= " + x.c);
		x.c = 'a';
		System.out.println("2:x.c= " + x.c);
		f(x);
		System.out.println("3:x.c= " + x.c);
	}
}

class MathOps{
	public static void main(String []args) {
		Random rand = new Random(47);
		int i , j , k;
		j = rand.nextInt(100) + 1;
		System.out.println("j = " + j);
		k = rand.nextInt(100) + 1;
		System.out.println("k = " + k);
		i = j + k;
		System.out.println("i = " + i);
		
		float u , v , w;
		u = rand.nextFloat();
		System.out.println("u = " + u);
		v = rand.nextFloat() ;
		System.out.println("v = " + v);
		w = u + v;
		System.out.println("w = " + w);
	}
}

class AutoInc{
	public static void main(String []args) {
		int i = 1;
		System.out.println("i = " + i);
		System.out.println("++i = " + ++i);
		System.out.println("i++ = " + i++);
		System.out.println("i2 = " + i);
		System.out.println("--i = " + --i);
		System.out.println("i-- = " + i--);
		System.out.println("i3 = " + i);
 }
}
/* output
i = 1
++i = 2
i++ = 2
i2=3
--i = 2
i-- = 2
i3=1
*/

class Equaivalence{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1 == n2);
		System.out.println(n1 != n2);
 }
}

class EqualsMethod{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1.equals(n2));
 }
}

class Value{
	int i ;
}
class EqualsMethod2{
	public static void main(String []args) {
		Value v1 = new Value();
		Value v2 = new Value();
	 System.out.println(v1.equals(v2));
 }
}

class ShortCircuit{
	static boolean test1(int val){
		System.out.println("test1( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 1);
	}
	
	static boolean test2(int val){
		System.out.println("test2( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 2);
	}
	
	static boolean test3(int val){
		System.out.println("test3( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 3);
	}
	
	
	public static void main(String []args) {
		
		boolean b = test1(0) && test2(2) && test2(3);
		System.out.println("expression is : "  + b );
	}
}

class CommaOperator{
	public static void main(String []args) {
		for(int i = 1, j = i + 10; i < 5;i++,j = i*2){
			System.out.println("i =  "  +  i + " j = "  + j);
		}
 }
}


class ForEachFloat{
	public static void main(String []args) {
		Random rand = new Random(47);
		float f[] = new float[10];
		for(int i = 0; i < 10;i++){
			f[i] = rand.nextFloat();
		}
		
		for(float x:f){
			System.out.println("x =  " + x);
		}
		
		for(char c:"my name".toCharArray()){
			System.out.println("c =  " + c);
		}
 }
}

class LableedWhile{
	public static void main(String []args) {
		int i = 0;
		outer:
		while(true){
			System.out.println("Outer while loop");
			while(true){
				i++;
				System.out.println("i = " + i);
				if(i == 1){
					System.out.println("continue");
					continue;
				}
				if(i == 3){
					System.out.println("continue Outer");
					continue outer;
				}
				if(i == 5){
					System.out.println("break");
					break;
				}
				if(i == 7){
					System.out.println("break Outer");
					break outer;
				}
			}
		}
 }
}

class VoewlsAndConson{
	public static void main(String []args) {
		Random rand = new Random(47);
		for(int i = 0; i < 100;i++){
			int c = rand.nextInt(26) + 'a';
			System.out.println("c = " + c);
			switch(c){
				case 'a':
				case 'b':
				case 'c': System.out.println("vowel");break;
				case 'y':
				case 'w':
				case 'z':System.out.println("consonant");break;
				default:System.out.println("xxxx");
			}
		}
 }
}

class Flower{
	int petalCount = 0;
	String s = "init value";
	
	Flower(int peta){
		petalCount = peta;
		System.out.println("Flower(int peta)" );
	}
	
	Flower(String ss){
		s = ss;
		System.out.println("Flower(String ss) " );
	}
	
	
	Flower(String s,int patails){
		this(patails);
		this.s = s;
		System.out.println("Flower(String s,int patails) ");
	}
	
	Flower(){
		this("xxx",1);
		System.out.println("Flower() ");
	}
	public static void main(String []args) {
		Flower x = new Flower();
		
	}
}


class Book{
 boolean checkedOut = false;
 Book(boolean checkedOut){
 	this.checkedOut = checkedOut;
 }
 void checkIn(){
 	checkedOut = false;
 }
 protected void finalize(){
 	if(checkedOut){
 		System.out.println(" protected void finalize：error ");
 	}
}
}

class Tcondition{
	public static void main(String []args) {
		Book novel = new Book(true);
		novel.checkIn();
		new Book(true);
		System.gc(); //進行強制終結動作
	}
}


class ArrayClassObj{
	public static void main(String []args) {
		Random rand = new Random (46);
		Integer []a = new Integer[rand.nextInt(20)];
		System.out.println("a.length = " + a.length);
		for(int i= 0; i < a.length;i++){
			a[i] = rand.nextInt(500);
		}
		System.out.println(Arrays.toString(a));
		
	}
}

輸出結果：

原始碼：

//: HelloDate.java
import java.util.*;
//import static net.mindview.until.Print.*;
/** the first Thinking in java example program
  * display a string and today's date
  * @author wengyongsheng 
  * @version 4.0 
*/
public class HelloDate{
	/**
	* @param args array of string arguments
	*/
  public static void main(String []args) {
  System.out.println("Hello,It's: ");
  System.out.println(new Date());
//  print("Hello,It's: ");
}
}

class Tank{
	 int level;
}

class Assignment{
	public static void main(String []args) {
		Tank t1 = new Tank();
		Tank t2 = new Tank();
		t1.level = 9;
		t2.level = 47;
		System.out.println("1:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
    t1 = t2;
    System.out.println("2:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
		
		t1.level = 27;
		System.out.println("3:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);                   		                   
	}
}

class Letter{
	 char c;
}

class PassObject{
	static void f(Letter y){
		y.c = 'z';
	}
	public static void main(String []args) {
		Letter x = new Letter();
		System.out.println("1:x.c= " + x.c);
		x.c = 'a';
		System.out.println("2:x.c= " + x.c);
		f(x);
		System.out.println("3:x.c= " + x.c);
	}
}

class MathOps{
	public static void main(String []args) {
		Random rand = new Random(47);
		int i , j , k;
		j = rand.nextInt(100) + 1;
		System.out.println("j = " + j);
		k = rand.nextInt(100) + 1;
		System.out.println("k = " + k);
		i = j + k;
		System.out.println("i = " + i);
		
		float u , v , w;
		u = rand.nextFloat();
		System.out.println("u = " + u);
		v = rand.nextFloat() ;
		System.out.println("v = " + v);
		w = u + v;
		System.out.println("w = " + w);
	}
}

class AutoInc{
	public static void main(String []args) {
		int i = 1;
		System.out.println("i = " + i);
		System.out.println("++i = " + ++i);
		System.out.println("i++ = " + i++);
		System.out.println("i2 = " + i);
		System.out.println("--i = " + --i);
		System.out.println("i-- = " + i--);
		System.out.println("i3 = " + i);
 }
}
/* output
i = 1
++i = 2
i++ = 2
i2=3
--i = 2
i-- = 2
i3=1
*/

class Equaivalence{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1 == n2);
		System.out.println(n1 != n2);
 }
}

class EqualsMethod{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1.equals(n2));
 }
}

class Value{
	int i ;
}
class EqualsMethod2{
	public static void main(String []args) {
		Value v1 = new Value();
		Value v2 = new Value();
	 System.out.println(v1.equals(v2));
 }
}

class ShortCircuit{
	static boolean test1(int val){
		System.out.println("test1( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 1);
	}
	
	static boolean test2(int val){
		System.out.println("test2( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 2);
	}
	
	static boolean test3(int val){
		System.out.println("test3( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 3);
	}
	
	
	public static void main(String []args) {
		
		boolean b = test1(0) && test2(2) && test2(3);
		System.out.println("expression is : "  + b );
	}
}

class CommaOperator{
	public static void main(String []args) {
		for(int i = 1, j = i + 10; i < 5;i++,j = i*2){
			System.out.println("i =  "  +  i + " j = "  + j);
		}
 }
}


class ForEachFloat{
	public static void main(String []args) {
		Random rand = new Random(47);
		float f[] = new float[10];
		for(int i = 0; i < 10;i++){
			f[i] = rand.nextFloat();
		}
		
		for(float x:f){
			System.out.println("x =  " + x);
		}
		
		for(char c:"my name".toCharArray()){
			System.out.println("c =  " + c);
		}
 }
}

class LableedWhile{
	public static void main(String []args) {
		int i = 0;
		outer:
		while(true){
			System.out.println("Outer while loop");
			while(true){
				i++;
				System.out.println("i = " + i);
				if(i == 1){
					System.out.println("continue");
					continue;
				}
				if(i == 3){
					System.out.println("continue Outer");
					continue outer;
				}
				if(i == 5){
					System.out.println("break");
					break;
				}
				if(i == 7){
					System.out.println("break Outer");
					break outer;
				}
			}
		}
 }
}

class VoewlsAndConson{
	public static void main(String []args) {
		Random rand = new Random(47);
		for(int i = 0; i < 100;i++){
			int c = rand.nextInt(26) + 'a';
			System.out.println("c = " + c);
			switch(c){
				case 'a':
				case 'b':
				case 'c': System.out.println("vowel");break;
				case 'y':
				case 'w':
				case 'z':System.out.println("consonant");break;
				default:System.out.println("xxxx");
			}
		}
 }
}

class Flower{
	int petalCount = 0;
	String s = "init value";
	
	Flower(int peta){
		petalCount = peta;
		System.out.println("Flower(int peta)" );
	}
	
	Flower(String ss){
		s = ss;
		System.out.println("Flower(String ss) " );
	}
	
	
	Flower(String s,int patails){
		this(patails);
		this.s = s;
		System.out.println("Flower(String s,int patails) ");
	}
	
	Flower(){
		this("xxx",1);
		System.out.println("Flower() ");
	}
	public static void main(String []args) {
		Flower x = new Flower();
		
	}
}


class Book{
 boolean checkedOut = false;
 Book(boolean checkedOut){
 	this.checkedOut = checkedOut;
 }
 void checkIn(){
 	checkedOut = false;
 }
 protected void finalize(){
 	if(checkedOut){
 		System.out.println(" protected void finalize：error ");
 	}
}
}

class Tcondition{
	public static void main(String []args) {
		Book novel = new Book(true);
		novel.checkIn();
		new Book(true);
		System.gc(); //進行強制終結動作
	}
}


class ArrayClassObj{
	public static void main(String []args) {
		Random rand = new Random (46);
		Integer []a = new Integer[rand.nextInt(20)];
		System.out.println("a.length = " + a.length);
		for(int i= 0; i < a.length;i++){
			a[i] = rand.nextInt(500);
		}
		System.out.println(Arrays.toString(a));
		
	}
}

class VarArgs{
	
	static void printArray(Object [] args) {
		for(Object obj : args){
			System.out.println("obj = " + obj);
		}
	}
	
	public static void main(String []args) {
		printArray(new Object[]
		           {new Integer(10),
		           	new Integer(20),
		           	new Integer(30)});

    printArray(new Object[]
		           {"one",
		           	"two",
		            "thress"});
	}
}

結果輸出：

JAVA SE5後新可變引數方法：

原始碼：

//: HelloDate.java
import java.util.*;
//import static net.mindview.until.Print.*;
/** the first Thinking in java example program
  * display a string and today's date
  * @author wengyongsheng 
  * @version 4.0 
*/
public class HelloDate{
	/**
	* @param args array of string arguments
	*/
  public static void main(String []args) {
  System.out.println("Hello,It's: ");
  System.out.println(new Date());
//  print("Hello,It's: ");
}
}

class Tank{
	 int level;
}

class Assignment{
	public static void main(String []args) {
		Tank t1 = new Tank();
		Tank t2 = new Tank();
		t1.level = 9;
		t2.level = 47;
		System.out.println("1:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
    t1 = t2;
    System.out.println("2:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);
		
		t1.level = 27;
		System.out.println("3:t1.level = " + t1.level + 
		                   " t2.level = " + t2.level);                   		                   
	}
}

class Letter{
	 char c;
}

class PassObject{
	static void f(Letter y){
		y.c = 'z';
	}
	public static void main(String []args) {
		Letter x = new Letter();
		System.out.println("1:x.c= " + x.c);
		x.c = 'a';
		System.out.println("2:x.c= " + x.c);
		f(x);
		System.out.println("3:x.c= " + x.c);
	}
}

class MathOps{
	public static void main(String []args) {
		Random rand = new Random(47);
		int i , j , k;
		j = rand.nextInt(100) + 1;
		System.out.println("j = " + j);
		k = rand.nextInt(100) + 1;
		System.out.println("k = " + k);
		i = j + k;
		System.out.println("i = " + i);
		
		float u , v , w;
		u = rand.nextFloat();
		System.out.println("u = " + u);
		v = rand.nextFloat() ;
		System.out.println("v = " + v);
		w = u + v;
		System.out.println("w = " + w);
	}
}

class AutoInc{
	public static void main(String []args) {
		int i = 1;
		System.out.println("i = " + i);
		System.out.println("++i = " + ++i);
		System.out.println("i++ = " + i++);
		System.out.println("i2 = " + i);
		System.out.println("--i = " + --i);
		System.out.println("i-- = " + i--);
		System.out.println("i3 = " + i);
 }
}
/* output
i = 1
++i = 2
i++ = 2
i2=3
--i = 2
i-- = 2
i3=1
*/

class Equaivalence{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1 == n2);
		System.out.println(n1 != n2);
 }
}

class EqualsMethod{
	public static void main(String []args) {
		Integer n1 = new Integer(47);
		Integer n2 = new Integer(47);
		
		System.out.println(n1.equals(n2));
 }
}

class Value{
	int i ;
}
class EqualsMethod2{
	public static void main(String []args) {
		Value v1 = new Value();
		Value v2 = new Value();
	 System.out.println(v1.equals(v2));
 }
}

class ShortCircuit{
	static boolean test1(int val){
		System.out.println("test1( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 1);
	}
	
	static boolean test2(int val){
		System.out.println("test2( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 2);
	}
	
	static boolean test3(int val){
		System.out.println("test3( " + val + " )");
		System.out.println("result: "  + (val <1) );
		return (val < 3);
	}
	
	
	public static void main(String []args) {
		
		boolean b = test1(0) && test2(2) && test2(3);
		System.out.println("expression is : "  + b );
	}
}

class CommaOperator{
	public static void main(String []args) {
		for(int i = 1, j = i + 10; i < 5;i++,j = i*2){
			System.out.println("i =  "  +  i + " j = "  + j);
		}
 }
}


class ForEachFloat{
	public static void main(String []args) {
		Random rand = new Random(47);
		float f[] = new float[10];
		for(int i = 0; i < 10;i++){
			f[i] = rand.nextFloat();
		}
		
		for(float x:f){
			System.out.println("x =  " + x);
		}
		
		for(char c:"my name".toCharArray()){
			System.out.println("c =  " + c);
		}
 }
}

class LableedWhile{
	public static void main(String []args) {
		int i = 0;
		outer:
		while(true){
			System.out.println("Outer while loop");
			while(true){
				i++;
				System.out.println("i = " + i);
				if(i == 1){
					System.out.println("continue");
					continue;
				}
				if(i == 3){
					System.out.println("continue Outer");
					continue outer;
				}
				if(i == 5){
					System.out.println("break");
					break;
				}
				if(i == 7){
					System.out.println("break Outer");
					break outer;
				}
			}
		}
 }
}

class VoewlsAndConson{
	public static void main(String []args) {
		Random rand = new Random(47);
		for(int i = 0; i < 100;i++){
			int c = rand.nextInt(26) + 'a';
			System.out.println("c = " + c);
			switch(c){
				case 'a':
				case 'b':
				case 'c': System.out.println("vowel");break;
				case 'y':
				case 'w':
				case 'z':System.out.println("consonant");break;
				default:System.out.println("xxxx");
			}
		}
 }
}

class Flower{
	int petalCount = 0;
	String s = "init value";
	
	Flower(int peta){
		petalCount = peta;
		System.out.println("Flower(int peta)" );
	}
	
	Flower(String ss){
		s = ss;
		System.out.println("Flower(String ss) " );
	}
	
	
	Flower(String s,int patails){
		this(patails);
		this.s = s;
		System.out.println("Flower(String s,int patails) ");
	}
	
	Flower(){
		this("xxx",1);
		System.out.println("Flower() ");
	}
	public static void main(String []args) {
		Flower x = new Flower();
		
	}
}


class Book{
 boolean checkedOut = false;
 Book(boolean checkedOut){
 	this.checkedOut = checkedOut;
 }
 void checkIn(){
 	checkedOut = false;
 }
 protected void finalize(){
 	if(checkedOut){
 		System.out.println(" protected void finalize：error ");
 	}
}
}

class Tcondition{
	public static void main(String []args) {
		Book novel = new Book(true);
		novel.checkIn();
		new Book(true);
		System.gc(); //進行強制終結動作
	}
}


class ArrayClassObj{
	public static void main(String []args) {
		Random rand = new Random (46);
		Integer []a = new Integer[rand.nextInt(20)];
		System.out.println("a.length = " + a.length);
		for(int i= 0; i < a.length;i++){
			a[i] = rand.nextInt(500);
		}
		System.out.println(Arrays.toString(a));
		
	}
}

class VarArgs{
	
	static void printArray(Object [] args) {
		for(Object obj : args){
			System.out.println("obj = " + obj);
		}
	}
	
	public static void main(String []args) {
		printArray(new Object[]
		           {new Integer(10),
		           	new Integer(20),
		           	new Integer(30)});

    printArray(new Object[]
		           {"one",
		           	"two",
		            "thress"});
	}
}

class NewVarArgs{
	
	static void printArray(Object ... args) {
		for(Object obj : args){
			System.out.println("obj = " + obj);
		}
	}
	
	public static void main(String []args) {
		printArray(
		            new Integer(1),
		           	new Integer(2),
		           	new Integer(3));

    printArray("one1",
		           	"two2",
		            "thress3");
	}
}

結果輸出：
可變引數的類可以為任何型別，包括基本型別
1. 比如：String型別
2. 比如：Int型別：
可變引數的過載

可變引數過載舉例（引數只有可變引數）：
可變引數過載舉例（引數有可變引數和不變引數）：

列舉型別

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