多项选择题
Given: Which three are valid?（）
A.p0 = p1; B.p1 = p2; C.p2 = p4; D.p2 = (ClassC)p1; E.p1 = (ClassB)p3; F.p2 = (ClassC)p4;
Given: What is the result?（）A.CanadaB.null CanadaC.Can...
单项选择题
Given: What is the result?（）
A.Canada B.null Canada C.Canada null D.Canada Canada E.Compilation fails due to an error on line 26. F.Compilation fails due to an error on line 29.
Given: What is the result? （）A.threeB.otherC.An except...
Given: What is the result? （）
A.three B.other C.An exception is thrown at runtime. D.Compilation fails because of an error on line 12. E.Compilation fails because of an error on line 13. F.Compilation fails because of an error on line 15.
Given: What is the result?（）A.test endB.Compilation fa...
A.test end B.Compilation fails. C.test runtime end D.test exception end E.Throwable is thrown by main at runtime.
