几个谜题深入了解java.docxVIP

在2009年的JavaOne大会上，Joshua Bloch和Neal Gafter又为我们带来的7道谜题，挺有意思的。大家不妨看看。摘自：Return of the Puzzlers: Schlock and Awe Joshua Bloch, Google, Inc.; Neal Gafter, Microsoft /learning/javaoneonline/sessions/2009/pdf/TS-5186.pdf1.Lifes Persistent Questions Java code public class SimpleQuestion { static booleanyesOrNo(String s) { s = s.toLowerCase(); if (s.equals(yes) || s.equals(y) || s.equals(t)) { s = true; } return Boolean.getBoolean(s); } public static void main(String[] args) {System.out.println(yesOrNo(true) + + yesOrNo(Yes)); }}问题：程序打印什么？如果熟悉Boolean.getBoolean（）这个方法的话，应该不会出错。方法的功能参考文档。2.Instruments of TortueJava code import java.util.Arrays;import java.util.Collection;import java.util.HashSet;public class InstrumentedHashSetE extends HashSetE { private intaddCount = 0; @Override public boolean add(E e){addCount++; return super.add(e); } @Override public booleanaddAll(Collection? extends E c){addCount += c.size(); return super.addAll(c); } public static void main(String[] args) {InstrumentedHashSetString s = new InstrumentedHashSetString();s.addAll(Arrays.asList(Accordion,Banjo,Kazoo));System.out.println(s.addCount); }}问题：打印结果是什么？这个看第一遍可能会出错，不过也算容易理解。3.Iterator TitillatorJava code import java.util.Iterator;import java.util.NoSuchElementException;public abstract class AbstractIteratorT implements IteratorT { T next = nextElement(); public booleanhasNext() { return next != null; } public T next() { if (next == null) { throw new NoSuchElementException(); } T result = next; next = nextElement(); return result; } public void remove() { throw new UnsupportedOperationException(); } protected abstract T nextElement(); private static IteratorCharacter test(final String s) { return new AbstractIteratorCharacter() { private int cursor = 0; protected Character nextElement() {