importjava.util.*;classBanana3{publicstaticvoidmain(String[]args){intx=2;Banana3b=newBanana3();b.go(x);}static{x+=x;}voidgo(intx){++x;System.out.println(x);}}结果为:()
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类Student代码如下:classStudent{Stringname;intage;Student(Stringnm){name=nm;}}执行语句Studentstu=newStudent()后,字段age的值是哪项?()
A. 0
C. false
D. 编译错误
classTestReference{publicstaticvoidmain(String[]args){intx=2;TestReferencetr=newTestReference();System.out.print(x);tr.change(x);System.out.print(x);}publicvoidchange(intnum){num=num+1;}}程序运行后的输出是哪项()?
A. 23
B. 21
C. 22
D. 编译错误
classParserextendsUtils{publicstaticvoidmain(String[]args){try{System.out.print(newParser().getInt("42"));}catch(NumberFormatExceptionn){System.out.println("NFExc");}}intgetInt(Stringarg)throwsNumberFormatException{returnInteger.parseInt(arg);}}classUtils{intgetInt(Stringarg){return42;}}结果为:()
A. 42
B. NFExc
C. 42NFExc
D. 编译失败
importjava.io.PrintWriter;classDoFormat{publicstaticvoidmain(String[]args){intx=42;inty=12345;floatz=7;System.out.format("-%4d-",x);System.out.format("-%4d-",y);System.out.format("-%4.1d-",z);}}结果为:()
A. 编译失败
B. -42--1234--7.0-
C. -42--1234--7.0-
D. 运行时异常被抛出