public void foo( boolean a, boolean b ){ if( a ) { System.out.println( “A” ); } else if ( a && b ) { System.out.println( “A&&B” ); } else { 17. if ( !b ) { System.out.println( “notB” ); } else { System.out.println( “ELSE” ); } } } What is correct?()
interface Data { public void load(); } abstract class Info { public abstract void load(); } Which class correctly uses the Data interface and Info class?()
class Thread2 implements Runnable { void run() { System.out.print("go "); } public static void main(String [] args) { Thread2 t2 = new Thread2(); Thread t = new Thread(t2); t.start(); } } 结果为()
Given:10. interface Data { public void load( ); }11. abstract class Info { public abstract void load( ); }Which class correctly uses the Data interface and Info class?()()
class TestA { public void start() { System.out.println(”TestA”); } } public class TestB extends TestA { public void start() { System.out.println(”TestB”); } public static void main(String[] args) { ((TestA)new TestB()).start(); } } What is the result?()
Less Test{ public static void main(String[] args){ for(int x=0;x<7;++x){ int y=2; x=++y; } System.out.println(“y=”+y); } } 结果为:()
If a void occurs in the cargo hold, it is better to()to control the broken stowage.
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?()
10. interface Jumper { public void jump(); } ...... 20. class Animal {} ...... 30. class Dog extends Animal { 31. Tail tail; 32. } ...... 40. class Beagle extends Dog implements Jumper { 41. public void jump() { } 42. } ....... 50. class Cat implements Jumper { 51. public void jump() { } 52. } Which three are true?()
interface Animal { void soundOff(); } class Elephant implements Animal { public void soundOff() { System.out.println(“Trumpet”); } } class Lion implements Animal { public void soundOff() { System.out.println(“Roar”); } } class Alpha1 { static Animal get( String choice ) { if ( choice.equalsIgnoreCase( “meat eater” )) { return new Lion(); } else { return new Elephant(); } } } Which compiles?()