单项选择题

A. Foo has the value “”
B. Foo has the value null
C. An exception is thrown
D. The code will not compile

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单项选择题 public class Test {  public static void main (String[]args) {  String foo = args[1];  String bar = args[2];  String baz = args[3];  System.out.printIn(“baz = ” + baz);  }  }  And the output:  Baz = 2  Which command line invocation will produce the output?()

单项选择题 1. package foo;  2.    3. import java.util.Vector;  4.    5. private class MyVector extends Vector {  6. int i = 1;  7. public MyVector()  {  8. i = 2;  9.    }  10. }  11.    12. public class MyNewVector extends MyVector {  13. public MyNewVector ()  {  14. i = 4;  15. }  16. public static void main (String args [])  {  17. MyVector v = new MyNewVector();  18.   }  19. }     The file MyNewVector.java is shown in the exhibit.  What is the result?()

单项选择题 class super {  public int getLength()  {return 4;}  }  public class Sub extends Super {  public long getLength() {return 5;}  public static void main (String[]args)  {  super sooper = new Super ();  Sub sub = new Sub();  System.out.printIn(  sooper.getLength()+ “,” + sub.getLength()   };  }  What is the output?()