public class Pet{ private String name; public Pet(){ System.out.print(1); } public Pet(String name){ System.out.print(2); } } public class Dog extends Pet{ public Dog(){ System.out.print(4); } public Dog(String name){ this(); System.out.print(3); } } 执行new Dog(“棕熊”);后程序输出是哪项?()
public class Parent{ 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?()
10. class MakeFile { 11. public static void main(String[] args) { 12. try { 13. File directory = new File(”d”); 14. File file = new File(directory,”f”); 15. if(!file.exists()) { 16. file.createNewFile(); 17. } 18. } catch (IOException e) { 19. e.printStackTrace 20. } 21. } 22. } The current directory does NOT contain a directory named “d.” Which three are true?()
The public store is to close at 9:30 p.m. ()no need to worry; it is just 7:30 p.m.
public class X { public static void main (String[] args) { byte b = 127; byte c = 126; byte d = b + c; } } Which statement is true?()
public class Mycircle { public double radius; public double diameter; public void setRadius(double radius) this.radius = radius; this.diameter= radius * 2; } public double getRadius() { return radius; } Which statement is true?()
While considering security, which of the following is the BEST place for a public web server accessible via the Internet? ()
public static void main(String[]args){ String str="null"; if(str==null){ System.out.println("null"); }else(str.length()==0){ System.out.println("zero"); }else{ System.out.println("some"); } } What is the result?()
Given the command line java Pass2 and: public class Pass2 { public void main(String [] args) { int x=6; Pass2 p = new Pass2(); p.doStuff(x); System.out.print(” main x = “+ x); } void doStuff(int x) { System.out.print(” doStuffx = “+ x++); } } What is the result?()
23.int z=5; 24. 25. public void stuff1(int x) { 26. assert (x> 0); 27. switch(x) { 28. case 2: x= 3; 29. default: assert false; } } 30. 31. private void stuff2(int y) { assert (y < 0); } 32. 33. private void stuff3() { assert (stuff4O); } 34. 35. private boolean stuff4() { z = 6; return false; } Which is true?()