hi hi ouch!
ouch! howdy ouch!
hi howdy ouch!
编译失败
运行的咐候有异常抛出
第1题:
现有: class Tree { private static String tree = "tree "; String getTree () { return tree; } } class Elm extends Tree { private static String tree = "elm "; public static void main (String [] args) { new Elm() .go (new Tree()) ; } } void go (Tree t) { String s = t.getTree () +Elm.tree + tree + (new Elm() .getTree ()) ; System.out.println (s) ;} 结果为:()
第2题:
现有 class Parser extends Utils { public static void main (String [] args) { try { System.out.print (new Parser () .getlnt ("42")) } catch (Exception e) { System.out.println ("Exc") ; } } int getlnt (String arg) throws Exception { return Integer.parselnt (arg) ; } } class Utils { int getlnt () { return 42; } } 结果是什么?()
第3题:
interface A{
int x = 0;
}
class B{
int x =1;
}
class C extends B implements A {
public void pX(){
System.out.println(x);
}
public static void main(String[] args) {
new C().pX();
}
}
错误。在编译时会发生错误(错误描述不同的JVM 有不同的信息,意思就是未明确的
x 调用,两个x 都匹配(就象在同时import java.util 和java.sql 两个包时直接声明Date 一样)。
对于父类的变量,可以用super.x 来明确,而接口的属性默认隐含为 public static final.所以可
以通过A.x 来明确。
第4题:
现有: class Guy { String greet() { return "hi"; } } class Cowboy extends Guy { String greet() { return. "howdy";}} class Wrangler extends Cowboy { String greet() { return "orch!"; } } class Greetings2 { public static void main (String [] args) { Guy g=new Wrangler(); Guy g2=new Cowboy(); Wrangler w2=new Wrangler(); System. out .print (g.greet()+g2.greet()+w2 .greet()); } } 结果是什么?()
第5题:
class Guy{String greet(){return “hi“}} class Cowboy extends Guy {String greet(){return“howdy”}} class Surfer extends Guy {String greet(){return“dudel”}} class Greetings{ public static void main (string[]args){ Guy[] guy= {new Guy(),new Cowboy(),new Surfer()}; for(Guy 0: guys) System.out.print(g.green()); } } 结果为:
第6题:
现有: class Parser (类)extends(继承) Utils { public static void main(String [] args) { System.out.print(输出打印)(new Parser().getInt("42")); } int getInt(String arg) { return Integer.parseInt(arg); } } class Utils { int getInt(String arg) throws Exception { return 42; } } 结果为:()
第7题:
class Guy { String greet() { return "hi "; } } class Cowboy extends Guy { String greet() { return "howdy "; } } class Wrangler extends Cowboy { String greet() { return "ouch! "; } } class Greetings2 { public static void main(String [] args) { Guy g = new Wrangler(); Guy g2 = new Cowboy(); Wrangler w2 = new Wrangler(); System.out.print(g.greet()+g2.greet()+w2.greet()); } } 结果是什么?()
第8题:
class A { public String toString () { return “4”; } } class B extends A { 8. public String toString () { return super.toString() + “3”; } } public class Test { public static void main(Stringargs) { System.out.printIn(new B()); } } What is the result?()
第9题:
class Mineral { static String shiny() { return "1"; } } class Granite extends Mineral { public static void main(String [] args) { String s = shiny() + getShiny(); s = s + super.shiny(); System.out.println(s); } static String getShiny() { return shiny(); } } 结果为:()
第10题:
public class X { public X aMethod() { return this;} } public class Y extends X { } Which two methods can be added to the definition of class Y?()