11.publicstaticvoidtest(Stringstr){12.if(str==null|str.lellgth()==0){13.System.out.println(”Stringisempty”);14.}else{15.System.out.println(”Stringisnotempty”);16.}17.}Andtheinvocation:31.test(llull);Whatistheresult?()
A.Auexceptionisthrownatruntime.
B.“Stringisempty”isprintedtooutput.
C.Compilationfailsbecauseofauerrorinline12.
D.“Stringisnotempty”isprintedtooutput.
第1题:
A.null
B.zero
C.some
D.Compilationfails.
E.Anexceptionisthrownatruntime.
第2题:
A.NULL
B.Compilationfails.
C.Thecoderunswithnooutput.
D.Anexceptionisthrownatruntime.
NULLshouldbe"null".
第3题:
第4题:
11.publicvoidtestIfA(){12.if(testIfB(”True”)){13.System.out.println(”True”);14.}else{15.System.out.println(”Nottrue”);16.}17.}18.publicBooleantestIfB(Stringstr){19.returnBoolean.valueOf(str);20.}WhatistheresultwhenmethodtestIfAisinvoked?()
A.True
B.Nottrue
C.Anexceptionisthrownatruntime.
D.Compilationfailsbecauseofanerroratline12.
E.Compilationfailsbecauseofanerroratline19.
第5题: