瑞海软件java面试题new

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1、瑞海软件Java面试题1.谈谈&和&&的区别2.数组有没有length()这个方法?String有没有length()这个方法?3.HashMap和Hashtable的区别4.Collection和Collections的区别5.Math.round(11.5)等於多少?Math.round(-11.5)等於多少?6.Strings=newString("xyz");创建了几个StringObject?,分别是什么？7.error和exception有什么区别?8.abstract的method是否可同

2、时是static,是否可同时是native，是否可同时是synchronized?9.接口是否可继承接口?抽象类是否可实现(implements)接口?抽象类是否可继承实体类(concreteclass)?10.当一个线程进入一个对象的一个synchronized方法后，其它线程是否可进入此对象的其它方法?11.try{}里有一个return语句，那么紧跟在这个try后的finally{}里的code会不会被执行，什么时候被执行，在return前还是后?12.问以下程序将会打印出什么?父类package

3、test;publicclassFatherClass{publicFatherClass(){System.out.println("FatherClassCreate");}}子类:packagetest;importtest.FatherClass;publicclassChildClassextendsFatherClass{publicChildClass(){System.out.println("ChildClassCreate");}publicstaticvoidmain(String

4、[]args){FatherClassfc=newFatherClass();ChildClasscc=newChildClass();}}补充完善以下程序，以实现设计2个线程，其中两个线程每次对j增加1，另外两个线程对j每次减少1。对j增减的时候不需要考虑顺序问题。WritetheSQLstatementsthatimplementthedatabaseschemathatcorrespondstothefollowingERmodel.Theentity“Child”isaweakentitywhi

5、chdependson“Employee”.Youranswershouldalsoincludethestatementoftherelevantintegrityconstraints.TheanswercanbegivenpurelyintermsoftwoCREATEstatements.答：Descriptionforthefollowingtwoquestions:Considerasmalldatabaseforalibrary.Thedatabasestoresgeneralinform

6、ationaboutbooks,thephysicalcopiesofeachbooktheyhaveinthelibrary,theirreadersandthebooks/copiesthatwereoraregivenoutonloan.Thisinformationisstoredinthefollowingrelations(primarykeysarerepresentedinboldunderlinedandforeignkeysinbolditalic(arrowsarealsodraw

7、nforforeignkeystoimprovereadability)):BookISBNtitleauthorspublisheryearpricePhysicalCopycatalogNoISBNlocationmaxDaysLoanoverdueChargePerDayReaderuserNamenameaddressmaxNoBooksForLoanLoanuserNamecatalogNodateOutdateInQuestion2[13]Expressthefollowingnatural

8、languagequeriesinSQL:a)Listthetitle,authors,andpriceforallthebookspublishedbyAddison-Wesleyin2000,inalphabeticalorderwithrespecttotitles.[2]b)Listthetitlesofallthebooksthatcanbetakenonloanformorethanthreedays.[2]c)Listhowm