多项选择题
class ClassA {}
class ClassB extends ClassA {}
class ClassC extends ClassA {}
and：
ClassA p0 = new ClassA（）；
ClassB p1 = new ClassB（）；
ClassC p2 = new ClassC（）；
ClassA p3 = new ClassB（）；
ClassA p4 = new ClassC（）；
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；
相关考题
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单项选择题
package geometry； public class Hypotenuse { public InnerTriangle it = new InnerTriangle（）； class InnerTriangle { public int base； public int height； } } Which is true about the class of an object that can reference the variable base？ （）
A. It can be any class.
B. No class has access to base.
C. The class must belong to the geometry package.
D. The class must be a subclass of the class Hypotenuse. -
单项选择题
1. public class Target { 2. private int i = 0； 3. public int addOne（） { 4. return ++i； 5. } 6. } And： 1. public class Client { 2. public static void main（String[] args） { 3. System.out.println（new Target（）.addOne（））； 4. } 5. } Which change can you make to Target without affecting Client？（）
A. Line 4 of class Target can be changed to return i++；
B. Line 2 of class Target can be changed to private int i = 1；
C. Line 3 of class Target can be changed to private int addOne（） {
D. Line 2 of class Target can be changed to private Integer i = 0； -
单项选择题
package test； class Target { public String name = “hello”； } What can directly access and change the value of the variable name？（）
A. any class
B. only the Target class
C. any class in the test package
D. any class that extends Target
