Foo.beta() is a valid invocation of beta().
Foo.alpha() is a valid invocation of alpha().
Method beta() can directly call method alpha().
Method alpha() can directly call method beta().
第1题:
10. class Foo { 11. static void alpha() { /* more code here */ } 12. void beta() { /* more code here */ } 13. } Which two are true?()
第2题:
class One { void foo() {} } class Two extends One { //insert method here } Which three methods, inserted individually at line 14, will correctly complete class Two?()
第3题:
A.int foo() { /* more code here */ }
B.void foo() { /* more code here */ }
C.public void foo() { /* more code here */ }
D.private void foo() { /* more code here */ }
E.protected void foo() { /* more code here */ }
第4题:
package sun.scjp; public enum Color { RED, GREEN, BLUE } package sun.beta; // insert code here public class Beta { Color g = GREEN; public static void main( String[] argv) { System.out.println( GREEN); } } The class Beta and the enum Color are in different packages. Which two code fragments, inserted individually at line 2 of the Beta declaration, will allow this code to compile?()
第5题:
1. class Alpha { void m1() {} } 2. class Beta extends Alpha { void m2() { } } 3. class Gamma extends Beta { } 4. 5. class GreekTest { 6. public static void main(String [] args) { 7. a Alpha [] a = {new Alpha(), new Beta(), new Gamma() }; 8. for(Alpha a2 : a) { 9. a2.m1(); 10. if (a2 instanceof Beta || a2 instanceof Gamma) 11. //insert code here 12. } 13. } 14. } 哪一行代码插入到第11行,将编译但是会在运行时产生异常?()
第6题:
现有包结构: com |-- x | |-- Alpha.class | | | |-- y | |-- Beta.class | |-- Gamma.class 和类: //insert code here import com.*; import com.x.y.*; class Test { Alpha a; Beta b; Gamma c; } 哪两行分别插入后可允许代码编译?()
第7题:
10. interface Foo { int bar(); } 11. public class Sprite { 12. public int fubar( Foo foo) { return foo.bar(); } 13. public void testFoo() { 14. fubar( 15. // insert code here 16.); 17. } 18. } Which code, inserted at line 15, allows the class Sprite to compile?()
第8题:
A.Alpha a = x;
B.Foo f = (Delta)x;
C.Foo f = (Alpha)x;
D.Beta b = (Beta)(Alpha)x;
第9题:
public class Team extends java.util.LinkedList { public void addPlayer(Player p) { add(p); } public void compete(Team opponent) { /* more code here */ } } class Player { /* more code here */ } Which two are true?()
第10题:
10. interface Foo {} 11. class Alpha implements Foo {} 12. class Beta extends Alpha {} 13. class Delta extends Beta { 14. public static void main( String[] args) { 15. Beta x = new Beta(); 16. // insert code here 17. } 18. } Which code, inserted at line 16, will cause a java.lang.ClassCastException?()