举一反三
- 给定代码如下: public abstract interface Frobnicate { public void twiddle(String s); } 以下哪个类是正确的?(). A: public abstract class Frob implements Frobnicate { public abstract void twiddle(String s) { } } B: public abstract class Frob implements Frobnicate { } C: public class Frob extends Frobnicate { public void twiddle(Integer i) { } } D: public class Frob implements Frobnicate { public void twiddle(Integer i) { } }
- Which two demonstrate an “is a” relationship？ （） A: public interface Person{} public class Employee extends Person{} B: public interface Shape{} public class Employee extends Shape{} C: public interface Color{} public class Employee extends Color{} D: public class Species{} public class Animal （private Species species；） E: interface Component{} Class Container implements Component （ Private Component[ ] children； ）
- 假设C和D是接口，下列定义哪个是正确的（） A: public class A implements C,D｛ ｝ B: public class A implements C implements D｛ ｝ C: public class A extends C,D｛ ｝ D: public class A extends C extends D｛ ｝
- A类同时实现接口B和接口C，正确的写法是： A: public class A implements B, implements C {...} B: public class A implements B, C {...} C: public class A interface B, iinterface C {...} D: public class A extends B, C {...}
- 下面哪些语法结构是不正确的（ ） A: public class A extends B implements C B: public class A implement A B C: public class A implements B,C,D D: public class A implements B
内容
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下列哪个方法可用于创建一个可运行的类（） A: public class X implements Runnable{public void run() {……}} B: public class X extends Thread{public void run() {……}} C: public class X extends Thread{public int run() {……}} D: public class X implements Runnable{protected void run() {……}}
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下列哪个方法可用于创建一个可运行的类X? A: public class X implements Runnable{ public void run(){......} } B: public class X implements Thread{ public void run(){......} } C: public class X implements Thread{ public int run(){......} } D: public class X extends Runnable{ public void run(){......} }
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（1+X）假设 C 是抽象类，I1 和 I2 是接口。下列关于抽象类或接口的定义，哪一个是正确的（ ）。 A: public class A extends C implements I1,I2{} B: public class A extends I1,I2 implements C{} C: public class A implements I1,I2 extends C {} D: public class A extends C, I1, I2 {}
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下列关于Test类的定义代码中，正确的是______。 A: class Test implements Runnable { public void run() {} public void someMethod() {} } B: class Test implements Runnable { public void run(); } C: class Test implements Runnable { public void someMethod(); } D: class Test implements Runnable { public void someMethod() {} }
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下面关于子类继承父类，正确的是（ ）。 A: public class Student extends People{} B: public class Student implements People{} C: public class Student extends Teacher People{} D: 以上都不正确