1. class super { 2. public float getNum() {return 3.0f;} 3. } 4. 5. public class Sub extends Super { 6. 7. } Which method, placed at line 6, will cause a compiler error?()
第1题:
1. public class Target { 2. private int i = 0; 3. public int addOne() { 4. return ++i; 5. } 6. } And: 1. public class Client { 2. public static void main(String[] args) { 3. System.out.println(new Target().addOne()); 4. } 5. } Which change can you make to Target without affecting Client?()
第2题:
1. public class a { 2. public void method1() { 3. try { 4. B b=new b(); 5. b.method2(); 6. // more code here 7. } catch (TestException te) { 8. throw new RuntimeException(te); 9. } 10. } 11. } 1. public class b { 2. public void method2() throws TestException { 3. // more code here 4. } 5. } 1. public class TestException extends Exception { 2. } Given: 31. public void method() { 32. A a=new a(); 33. a.method1(); 34. } Which is true if a TestException is thrown on line 3 of class b?()
第3题:
1. class BaseClass { 2. private float x = 1.of; 3. protected float getVar() { return x; } 4. } 5. class SubClass extends BaseClass { 6. private float x = 2.Of; 7. // insert code here 8. } Which two are valid examples of method overriding when inserted at line 7?()
第4题:
1. abstract class AbstractIt { 2. abstract float getFloat(); 3. } 4. public class AbstractTest extends AbstractIt { 5. private float f1 = 1.0f; 6. private float getFloat() { return f1; } 7. } What is the result?()
第5题:
class super { public float getNum() {return 3.0f;} } public class Sub extends Super { } Which method, placed at line 6, will cause a compiler error?()
第6题:
1. public interface A { 2. public void doSomething(String thing); 3. } 1. public class AImpl implements A { 2. public void doSomething(String msg) { } 3. } 1. public class B { 2. public A doit() { 3. // more code here 4. } 5. 6. public String execute() { 7. // more code here 8. } 9. } 1. public class C extends B { 2. public AImpl doit() { 3. // more code here 4. } 5. 6. public Object execute() { 7. // more code here 8. } 9. } Which statement is true about the classes and interfaces in the exhibit?()
第7题:
class Super { public int getLenght( ) { return 4; } } public class Sub extends Super { public long getLenght( ) { return 5; } public static void main(String[] args) { Super sooper = new Super( ); Sub sub = new Sub( ); System.out.println( sooper.getLenght( ) + “,” + sub.getLenght( ) ); } } What is the output?()
第8题:
1. class Super { 2. public float getNum() { return 3.0f; } 3. } 4. 5. public class Sub extends Super { 6. 7. } Which method, placed at line6, causes compilation to fail?()
第9题:
1. public class A { 2. public void doit() { 3. } 4. public String doit() { 5. return “a”; 6. } 7. public double doit(int x) { 8. return 1.0; 9. } 10.} What is the result?()
第10题:
Given: 1. public class Method Over { 2. public void set Var (int a, int b, float c) { 3. } 4. } Which two overload the set Var method()?