SCJP认证试题(四)

 /**
 *
 * @author yaoyuan
 */

12	public class Certkiller5{
13		public static void main(String[] yahoo){
14			for(int x=1;x<yahoo.length;x++){
15				System.out.print(yahoo[x] + " ");
16			}
17		}
18	}
19

/**
*and the command and line invocation java Certkiller5 a b c, What is the result?
*
*
*
*A a b
*B b c
*C a b c
*D Compilation fails
*E An exception is thrown at runtime
*/

[color=red]// Answer : B[/color]

/**
* 注意14行的,x的值
*
*/

 /**
 *
 * @author yaoyuan
 */
11	public static void certkiller(String str){	
12		int check = 4;
13		if(chect = str.length()){
14			System.out.print(str.charAt(check = 1) + "");
15		}else{
16			System.out.print(str.charAt(0) + "");
17		}
18	}

and the invocation:
13	certkiller("four");
14	certkiller("tee");
15	certkiller("to");

/**
*What is the result?
*
*
*
*A r,t,t
*B r,e,o
*C Compilation fails
*D An exception is thrown at runtime
*/

[color=red]// Answer : C[/color]

 /**
 *
 * @author yaoyuan
 */
11	public class Certkiller{
12		public static void main(String[] args){
13			String myProp = /*insert code here*/
14			System.out.println(myProp);
15
16

/**
*and the command line:
*java -D rop.custom = gobstopperCertkiller
*Which two placed on line 13, will produce the output gobstopper?(choose two)
*
*
*A System.load("prop,custom");
*B System.getenv("prop.custom");
*C System.property("prop.custom");
*D System.getProperty("prop.custom");
*E System.getProperties().getProperty("prop.custom");
*/

[color=red]// Answer : D E[/color]

 /**
 *
 * @author yaoyuan
 */
1package util;
2public class BitUtils{
3	public static void process(byte []){/*more code here*/}
4}

1package app;
2public class CertkillerApp{
3	public static void main(String[] args){
4		byte[] bytes = new byte[256];
5		//insert code here
6	}
7}

/**
*What is required at line 5 in class CertkillerApp to use the process method of BitUtils?
*
*
*
*A Process(bytes);
*B BitUtils.process(bytes);
*C Util.BitUtils.process(bytes);
*D CertkillerApp cannot use method in BitUtils
*E Import util.BitUtils.*; process(bytes);
*/

[color=red]// Answer : C[/color]

 /**
 *
 * @author yaoyuan
 */
public class Item{
	private String desc;

	public String getDescription(){
		return desc;
	}

	public void setDescription(String d){
		desc = 1;
	}

	public static void modifyDesc(Item item, String desc){
		item = new Item();
		item.setDescription(desc);
	}

	public static void main(String[] args){
		Item it = new Item();
		it.setDescription("Gobstopper");
		Item it2 = new Item();
		it2.setDescription("Fizzylifting");
		modifyDesc(it, "Scrumdiddlyumptious");
		System.out.println(it.getDescription());
		System.out.println(it2.getDescription());
	}
}

/**
*What is the out come of the code?
*
*
*A Compilation fails
*B Gobstopper
* Fizzylifting
*C Gobstopper
* Scrumdiddlyumptious
*D Scrumdiddlyumptious
* Fizzylifting
*E Scrumdiddlyumptious
* Scrumdiddlyumptious
*/

[color=red]// Answer : B[/color]

 /**
 *
 * @author yaoyuan
 */
class CertKiller1{
	public CertKiller1(){
		System.out.print(1);
	}
}

class CertKiller2 extends CertKiller1{
	public CertKiller2(){
		System.out.print(2);
	}
}

class CertKiller3 extends CertKiller2{
	public CertKiller3(){
		System.out.print(3);
	}
}

public class Numbers{
	public static void main(String[] args){
		new CertKiller3();
	}
}

/**
*What is the result when this code executed?
*
*
*A 1
*B 3
*C 123
*D 321
*E The code runs with no output
*/

[color=red]// Answer : C[/color]

 /**
 *
 * @author yaoyuan
 */

/**
*Place the code fragments in position to complete the Displayable interface.
*/
interface Reloadable{
	public void reload();
}

class Edit{
	public void edit(){
		/* Edit Here*/
	}
}

interface Displayable [place here] [place here]{
		[place here]
	}
}

/**
* Code Fragments
*
* extends public void display(); Reloadable
* implements public void display();/"Display"/}; Edit
*/

[color=red]// Answer :
// interface Displayable extends Reloadable{
// public void display();
// }[/color]

/**
 *
 * @author yaoyuan
 */
class CertKiller{
	public enum Direction{
		NORTH,SOUTH,EAST,WEST
	}

	public class Sprite{
14		//insert code here
	}
}

/**
*Which code ,inserted at line 14, allows the Sprite class to compile?
*
*
*A Direction d = NORTH
*B CertKiller.Direction = NORTH
*C Direction = Direction.NORTH
*D CertKiller.Direction d = CertKiller Direction.NORTH
*/

[color=red]// Answer : D[/color]

 /**
 *
 * @author yaoyuan
 */
10interface Foo{
11	int bar();
12}
13
14public class Beta{
15	
16	class A implements Foo{
17		public int bar(){return 1;}
18	}
19	
20	public int fubar(Foo foo){return foo.bar();}
21	
22	public void testFoo(){
23
24		class A implements Foo{
25			public int bar(){return 2;}
26		}
27
28		System.out.println(fubar(new A();));
29	}
30	
31	public static void main(String[] argv){
32		new Beta.testFoo();
33	}
34}

/**
*Which three statements are true?(choose three)
*
*
*A Compilation fails
*B The code compiles and the output is 2
*C If lines 16, 17 and 18 were removed, compilation would fail
*D If lines 24,25 and 26 were removed, compilation would fail.
*E If lines 16 ,17 and 18 were removed, the code would compiled and the output would be 2
*F If lines 24, 25 and 26 were removed, the code would compiled and the output would be 1
*/
[color=red]
// Answer : B E F
[/color]


/**
*
* @author yaoyuan
*/

/**
*Add methods to the Bate class to make it compile correctly
*/

class Alpha{
	public void bar(int...x){}
	public void bar(int x){}
}

public class Beta extends Alpha{
	[place here]
	[place here]
	[place here]
}

/**
* Methods
*
* private void bar(int x){} public void bar(int x){}
* public int bar(String x){return 1;} public Alpha bar(int x){}
* public void bar(int x, int y){} public int bar(int x){return x}
*/

[color=red]// Answer :
// public class Beta extends Alpha{
// public void bar(int x, int y){}
// public int bar(String x){return 1;}
// public void bar(int x){}
// }
//
//
[/color]