基础阶段综合模拟题

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1、基础阶段综合模拟测试题一：单选题1.Whichstatementaboutthegarbagecollectionmechanismaretrue?（B）A.Garbagecollectionrequireadditionalprogramcodeincaseswheremultiplethreadsarerunning.B.Theprogrammercanindicatethatareferencethroughalocalvariableisnolongerofinterest.C.Theprogramme

2、rhasamechanismthatexplicitandimmediatelyfreesthememoryusedbyJavaobjects.D.ThegarbagecollectionmechanismcanfreethememoryusedbyJavaObjectatexpectabletime.E.Thegarbagecollectionsystemneverreclaimsmemoryfromobjectswhilearestillaccessibletorunninguserthreads.2.Gi

3、vethefollowingmethod:1)publicvoidmethod(){2)Stringa,b;3)a=newString(“helloworld”);4)b=newString(“gameover”);5)System.out.println(a+b+”ok”);6)a=null;7)a=b;8)System.out.println(a);9)}Intheabsenceofcompileroptimization,whichistheearliestpointtheobjectareferredi

4、sdefinitelyhandtobegarbagecollection.（D）A.beforeline3B.beforeline5C.beforeline6D.beforeline7E.Beforeline9 3.Givethefollowingcode:DFpublicclassExample{publicstaticvoidmain(Stringargs[]){intl=0;do{System.out.println(“Doingitforlis:”+l);}while(--l>;0)System.out

5、.println(“Finish”);}}Whichwellbeoutput:A.Doingitforlis3B.Doingitforlis1CDoingitforlis2D.Doingitforlis0E.Doingitforlis–1F.Finish1.以下（C）是JAVA的保留字。（选择一项）A．Java  B.HelloC.classD.Class5.欲构造ArrayList类的一个实例，此类继承了List接口，下列哪个方法是正确的？BA、ArrayListmyList=newObject（）；B、Li

6、stmyList=newArrayList（）；C、ArrayListmyList=newList（）；D、ListmyList=newList（）；6.指出正确的表达式CDA、byte=128;B、Boolean=null;C、longl=0xfffL;D.double=0.9239d;7下面程序运行之后，变量x的值是（B）.（选择一项）......//swap方法的声明publicstaticvoidswap(inta,intb){intt=a;a=b;b=t;}//main方法publicstaticvo

7、idmain(Stringargs[]){intx=2;inty=3;swap(x,y);}A、2B、3C、4D、68下面变量var的作用域范围是（D）。（选择一项）2.//....3.intx;4.switch(x){5.case0:6.{7.intvar;8.//process9.}10.break;11.case1:12.{13.intvar1;14.//process15.}16.break;1.}A、1和16行之间B、4和8行之间C、6和8行之间D、6和14行之间9指出下列程序运行的结果Bpublic

8、classExample{　　Stringstr=newString("good");　　char[]ch={'a','b','c'};　　publicstaticvoidmain(Stringargs[]){　　　　Exampleex=newExample();　　　　ex.change(ex.str,ex.ch);　　　　System.out.print(ex.str+"and")