更多"现有:  package mypack;&ensp"的相关试题:
[单项选择] 现有: package mypack; import java.awt.Color; import java.awt.FlowLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class ButtList extends JFrame { public static void main(String[] args) { ButtList bl =new ButtList(); } ButtList(){ JPanel pl=new JPanel(); pl.setBackground (Color.pink); p1.add(new JButton("one")); p1.add(new JButton("Two")); p1.add(new JButton("Three")); add("South",p1); setLayout(new Fl.wLayout()); setSize(200,200); setVisible(true); } } 上述代码运行后的显示效果是哪项?()
A. 3个按钮从左到右排列在Frame的底部
B. 3个按钮从左到右排列在Frame的顶部
C. 按钮无法显示
D. 只有按钮Three显示出来并占据Frame整个区域
[多项选择] 1. int I=1, j=0 2. 3. switch(i) { 4. case 2: 5. j+=6; 6. 7. case 4: 8. j+=1; 9. 10. default: 11. j +=2; 12. 13. case 0: 14. j +=4; 15. } 16. What is the value of j at line 16?()
A. 0
B. 1
C. 2
D. 4
E. 6
[单项选择] int i= 1, j= 10 ; do ( if (i++> --j) continue; ) while (i<5); After execution, what are the values for I and j?()
A. i = 6 and j= 5
B. i = 5 and j= 5
C. i = 6 and j= 4
D. i = 5 and j= 6
E. i = 6 and j= 6
[多项选择] int i = 0, j = 5; tp; for (;;) { i++; for(;;) { if (i> --j) { break tp; break tp; } } System.out.println(“i=” +i “,j =”+j); } What is the result?()
A. i = 1, j = 0
B. i = 1, j = 4
C. i = 3, j = 4
D. i = 3, j = 0
E. Compilation fails.
[单项选择] int i = 0, j = 1; if ((i++ == 1) && (j++ == 2)) { i = 42; } System.out.println(“i = “ + i + “, j = “ + j); What is the result?()
A. i = 1, j = 2
B. i = 1, j = 1
C. i = 42, j = 2
D. i = 42, j = 1
E. Compilation fails.
[单项选择] int i= 1, j= 10 ; do ( if (i++> --j) continue; ) while (i<5); After execution, what are the values for I and j? ()
A. i = 6 and j= 5
B. i = 5 and j= 5
C. i = 6 and j= 4
D. i = 5 and j= 6
E. i = 6 and j= 6
[多项选择] int I=1, j=0 switch(i) { case 2: j+=6; case 4: j+=1; default: j +=2; case 0: j +=4; } What is the value of j at line 16?()
A. 0
B. 1
C. 2
D. 4
E. 6
[单项选择] Import java.applet.Applet; Import java.awt*; Public class ImageDemo extends Applet{ Image img; Public void init(){ Img=getImage(getCodeBase(),”11.gif”);//1 } Public void paint(Graphics g){ Int w=img.getHeight(this); Int h=img.getHeight(this); g.drawImage(img,120,60,w/2,h/2,this);//2 g. drawImage(img,150,0,w*2,h*2,this);//3 } }以上代码第()行将图像放大。
A. 1
B. 2
C. 3
D. 代码并没有将图像放大
[单项选择] 现有: class Pencil { public void write (String content){ System.out.println ("Write"+content); } } class RubberPencil extends Pencil{ public void erase (String content){ System.out.println ("Erase"+content); } } 执行下列代码的结果是哪项?() Pencil pen=new RubberPencil(); pen.write ("Hello"); pen.erase ("Hello");
A. Write Hello Erase Hello
B. Erase Hello Write Hello
C. 编译错误
D. 运行时抛出异常
[单项选择] 现有: class Pencil { public void write (String content){ System.out.println ("Write"+content); } } class RubberPencil extends Pencil{ public void write (String content){ System.out.println ("Rubber Write"+content); } public void erase (String content){ System.out.println ("Erase "+content); } } 执行下列代码的结果是哪项?() Pencil pen=new RubberPencil(); pen.write("Hello");
A. Write Hello
B. Rubber Write Hello
C. 编译错误
D. 运行时抛出异常
[单项选择] 现有: class TestA { public void start() { System.out.println("TestA"); } } public class TestB extends TestA { public void start() { System.out.println("TestB"); } public static void main (string[] args) ( ((TestA)new TestB()).start(); ) } 运行结果是哪项?()
A. TeStA
B. TeStB
C. 编译失败
D. 运行时抛出异常
[单项选择] 现有代码片段: String s="123"; String sl=S+456; 请问sl的结果是哪项?()
A. 123456
B. 579
C. 编译错误
D. 运行时抛出异常
[多项选择] 现有2个文件: package x; public class X{ public static void doX() {System.out.print("doX");} } 和: class Find{ public static void main(String [] args) { //insert code here } } 哪两行分别插入到类Find的第3行将编译并产生输出“doX”?()
A. doX();
B. X.doX();
C. x.X.doX();
D. x.X myX=new x.X();myX.doX();
[单项选择] 现有: 1. interface Animal { 2. void eat(); 3. } 4. 5. // insert code here 6. 7. public class HouseCat implements Feline { 8. public void eat() { } 9. } 和以下三个接口声明: interface Feline extends Animal { } interface Feline extends Animal { void eat(); } interface Feline extends Animal { void eat() { } } 分别插入到第 5 行,有多少行可以编译?()
A. 0
B. 1
C. 2
D. 3
[多项选择] 现有: public class TestDemo{ private int X-2; static int y=3; public void method(){ final int i=100; int j =10; class Cinner { public void mymethod(){ //Here } } } } 在Here处可以访问的变量是哪些?()
A. X
B. y
C. j
D. i
[单项选择] 现有: class WhileTests { public static void main (String [] args) { int X=5; while (++x<4) { --x; } System.out.println( "x="+x); } } 结果是什么?()
A. X=6
B. X=5
C. X=2
D. 编译失败
[单项选择] 现有: class Top { static int x=l; public Top (inty) { x*=3; } } class Middle extends Top { public Middle() {x+=1; ) public static void main (String [] args) { Middle m = new Middle(); System. out .println (x); } } 结果为:()
A. 1
B. 2
C. 3
D. 编译失败
[单项选择] 现有: class Output { public static void main (String[] args) { int i=5: System.out.print( "4"+i+""); System.out.print (i+5+"7"); System.out.println (i+"8"); } } 结果为:()
A. 99722
B. 955758
C. 4510758
D. 459722
[单项选择] 现有 public class Parentt public void change (int x){) ) public class Child extends Parent{ //覆盖父类change方法 } 下列哪个声明是正确的覆盖了父类的change方法?()
A. protected void change (int x){}
B. public void change(int x, int y){}
C. public void change (int x){}
D. public void change (String s){}