Compilation fails due to an error in line 23.
Compilation fails due to an error in line 29.
A ClassCastException occurs in line 29.
A ClassCastException occurs in line 31.
The value of all four objects prints in natural order.
第1题:
以下程序的运行结果为?
class ValHold{
public int i = 10;
}
public class ObParm{
public static void main(String argv[]){
ObParm o = new ObParm();
o.amethod();
}
public void amethod(){
int i = 99;
ValHold v = new ValHold();
v.i=30;
another(v,i);
System.out.print( v.i );
}
public void another(ValHold v, int i){
i=0;
v.i = 20;
ValHold vh = new ValHold();
v = vh;
System.out.print(v.i);
System.out.print(i);
}
}
A.10030
B. 20030
C. 209930
D. 10020
第2题:
class Beta { public static void main(String [] args) { Integer x = new Integer(6) * 7; if (x != 42) { System.out.print("42 "); } else if (x 〈 new Integer(44-1)) { System.out.println("less"); } else { System.out.print("done"); } } } 结果是什么?()
第3题:
Given: Integer i = new Integer (42); Long l = new Long (42); Double d = new Double (42.0); Which two expression evaluate to true?()
第4题:
public static void main( String[] args ) { Integer a = new Integer(10); Integer b = new Integer(10); Integer c = a; int d = 10; double e = 10.0; } Which three evaluate to true?()
第5题:
1. public class Test { 2. public static String output =””; 3. 4. public static void foo(int i) { 5. try { 6. if(i==1) { 7. throw new Exception(); 8. } 9. output += “1”; 10. } 11. catch(Exception e) { 12. output += “2”; 13. return; 14. } 15. finally { 16. output += “3”;17. } 18. output += “4”; 19. } 20. 21. public static void main(String args[]) { 22. foo(0); 23. foo(1); 24. 25. }26. } What is the value of the variable output at line 23?()
第6题:
10. class Inner { 11. private int x; 12. public void setX( int x) { this.x = x; } 13. public int getX() { return x; } 14. } 15. 16. class Outer { 17. private Inner y; 18. public void setY( Inner y) { this.y = y; } 19. public Inner getY() { return y; } 20. } 21. 22. public class Gamma { 23. public static void main( String[] args) { 24. Outer o = new Outer(); 25. Inner i = new Inner(); 26.int n=10; 27. i.setX(n); 28. o.setY(i); 29. // insert code here 30. System.out.println( o.getY().getX()); 31. } 32. } Which three code fragments, added individually at line 29, produce the output 100?()
第7题:
10. interface Foo { 11. int bar(); 12. } 13. 14. public 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?()
第8题:
n = 100;
i.setX( 100);
o.getY().setX( 100);
i = new Inner(); i.setX( 100);
o.setY( i); i = new Inner(); i.setX( 100);
i = new Inner(); i.setX( 100); o.setY( i);
第9题:
(i = = l)
(i = = d)
(d = = l)
(i.equals(d))
(i.equals(i))
(i.equals(42))
第10题:
Compilation will fail.
The program prints “0”.
The program prints “3”.
Compilation will succeed but an exception will be thrown at line 3.
第11题:
p.setWeight(420);
p.changePayload(420);
p = new Payload(420);
Payload.setWeight(420);
p = Payload.setWeight(420);
p = new Payload(); p.setWeight(420);
第12题:
(i ==1)
(i == d)
(d == 1)
(i.equals (d))
(d.equals (i))
(i.equals (42))
第13题:
public class Test { public static void add3 (Integer i) { int val = i.intValue(); val += 3; i = new Integer(val); } public static void main(String args[]) { Integer i = new Integer(0); add3(i); System.out.println(i.intValue()); } } What is the result? ()
第14题:
public class Base { public static final String FOO = “foo”; public static void main(String[] args) { Base b = new Base(); Sub s = new Sub(); System.out.print(Base.FOO); System.out.print(Sub.FOO); System.out.print(b.FOO); System.out.print(s.FOO); System.out.print(((Base)s).FOO); } } class Sub extends Base {public static final String FOO=bar;} What is the result?()
第15题:
23. Object [] myObjects = { 24. new integer(12), 25. new String(”foo”), 26. new integer(5), 27. new Boolean(true) 28. }; 29. Arrays.sort(myObjects); 30. for( int i=0; i
第16题:
Integer i = new Integer (42); Long 1 = new Long (42); Double d = new Double (42.0); Which two expressions evaluate to True?()
第17题:
11. class Payload { 12. private int weight; 13. public Payload(int wt) { weight = wt; } 13. public void setWeight(mt w) { weight = w; } 15. public String toString { return Integer.toString(weight); } 16. } 17. 18. public class TestPayload { 19. static void changePayload(Payload p) { 20. /* insert code here */ 21. } 22. 23. public static void main(String[] args) { 24. Payload p = new Payload(); 25. p.setWeight(1024); 26. changePayload(p); 27. System.out.println(”The value of p is “+ p); 28. } 29. } Which statement, placed at line 20, causes the code to print “The value of p is 420.”?()
第18题:
public class test { public static void add3 (Integer i){ int val = i.intValue ( ); val += 3; i = new Integer (val); } public static void main (String args [ ] ) { Integer i = new Integer (0); add3 (i); system.out.printIn (i.intValue ( ) ); } } What is the result?()
第19题:
4:4:2:2
4:4:3:2
2:2:1:0
2:2:0:0
2:1:0:0
2:2:1:1
4:3:2:1
第20题:
three
other
Anexceptionisthrownatruntime.
Compilationfailsbecauseofanerroronline12.
Compilationfailsbecauseofanerroronline13.
Compilationfailsbecauseofanerroronline15.
第21题:
0
3
Compilation fails.
An exception is thrown at runtime.
第22题:
less
42
done
编译失败
第23题:
foofoofoofoofoo
foobarfoobarbar
foobarfoofoofoo
foobarfoobarfoo
barbarbarbarbar
foofoofoobarbar
foofoofoobarfoo