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Listing 7 - Question 13.
/*File Q13.java ************************************************/import java.util.*; public class Q13{ArrayList<Integer>var1 = new ArrayList<Integer>();void runIt(){var1.add(new Integer(1)); var1.add(new Integer(2));var1.add(new Integer(3));//Get an iterator Iterator iter = var1.iterator();//Perform the iterationwhile(iter.hasNext()){ System.out.println(iter.next().intValue());}//end while loop}//end runItpublic static void main(String[] args){new Q13().runIt(); }//end main}//end class Q13//=============================================//
Figure 5 - Question 13.
1 23

Answer 13

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Answers

Answer 13

False. This program produces the error shown in Figure 6 below. You must qualify the iterator as shown in Listing 8 to correct the error. If you don't qualify the iterator, the reference is retrieved fromthe list as type Object. The Object class neither defines nor inherits a method named intValue.

Listing 8 - Answer 13.
/*File A13.java ************************************************/import java.util.*; public class A13{ArrayList<Integer>var1 = new ArrayList<Integer>();void runIt(){var1.add(new Integer(1)); var1.add(new Integer(2));var1.add(new Integer(3));//Get an iterator Iterator<Integer>iter = var1.iterator();//Perform the iteration while(iter.hasNext()){System.out.println(iter.next().intValue()); }//end while loop}//end runItpublic static void main(String[]args){ new Q13().runIt();}//end main }//end class A13//=============================================//
Figure 6 - Answer 13.
Q13.java:22: error: cannot find symbol System.out.println(iter.next().intValue());^ symbol: method intValue()location: class Object 1 error

Back to Question 13

Answer 12

False. This program produces the compiler error shown in Figure 7 below. This is the result of attempting to store an object's reference of type String in acollection reserved exclusively for references to objects of type Date.

Figure 7 - Answer 12.
Q12.java:13: error: no suitable method found for add(String) var1.add("abcd");^ method ArrayList.add(int,Date) is not applicable(actual and formal argument lists differ in length) method ArrayList.add(Date) is not applicable(actual argument String cannot be converted to Date by method invocation conversion)1 error

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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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