多项选择题
A. Class B’s constructor is public.
B. Class B’s constructor has no arguments.
C. Class B’s constructor includes a call to this().
D. Class B’s constructor includes a call to super().
单项选择题 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?()
单项选择题 1. class Test { 2. private Demo d; 3. void start() { 4. d = new Demo(); 5. this.takeDemo(d); 6. } 7. 8. void takeDemo(Demo demo) { 9. demo = null; 10. demo = new Demo(); 11. } 12. } When is the Demo object, created on line 3, eligible for garbage collection?()
多项选择题 Whichtwocauseacompilererror?()