//Design an exception class for index out of bound in an one-domensional array p

Question

//Design an exception class for index out of bound in an one-domensional array public class IndexOutOfRange extends Exception { public IndexOutOfRange ( ) { super ("array index out of bound"); } public IndexOutOfRange (String msg) { super (msg); } } //Design a method to test the exception class above public void testException ( ) throws IndexOutOfRange { int capacity = 25; Integer [ ] x = new Integer [capacity]; for (int i = 0; i < 30; i++) { Integer num = new Integer (i); if (i >= capacity) throws new IndexOutOfRange ( ); else x[i] = num; } } //Design an exception handler for the exceptio above try { testException ( ); } catch (IndexOutOfRange ex) { } //Design a method to merge two existing text files, assume that they have been opened correctly public PrintWriter merge (Scanner file1, Scanner file2) { PrintWriter mergedFile = null; try { mergedFile = new PrintWriter ("file3.txt"); } catch (FileNotFoundException ex) { System.out.println ("fail to open file"); return mergedFile; } while (file1.hasNext ( )) { mergedFile.out.println (file1.nextLine ( )) } while (file2.hasNext ( )) { mergedFile.out.println (file2.nextLine ( )) } return mergedFile; } //Design a method to count the tokens in an existing and opened text file public int countTokens (Scanner inFile) { int count = 0; String inString = ""; while (inFile.hasNext ( )) inString += (inFile.nextLine ( )); int pos; while (true) { inString = inString.trim ( ); pos = inString.indexOf (" "); if (pos == -1) break; else { count++; inString = inString.substring (pos); } } return count; }

Explanation / Answer

import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;

public class JavaApplication3
{
    public static void main(String[] args)
    {
        try
        {
            testException ( );
        }
        catch (IndexOutOfRange ex)
        {
            System.out.println("Index out of bounds custom exception");
        }
    }
  
    public static void testException() throws IndexOutOfRange
    {
        int capacity = 25;
        Integer[] x = new Integer[capacity];
        for (int i = 0; i < 30; i++)
        {
            Integer num = new Integer (i);
            if (i >= capacity)
                throw new IndexOutOfRange();
            else
                x[i] = num;
        }
    }
  
     public static PrintWriter merge (Scanner file1, Scanner file2) throws java.io.FileNotFoundException
     {
         PrintWriter mergedFile = null;
         try
         {
             mergedFile = new PrintWriter ("file3.txt");
         }
         catch (FileNotFoundException ex)
         {
             System.out.println ("fail to open file");
             return mergedFile;
         }
         while (file1.hasNext ( ))
         {
             mergedFile.println(file1.nextLine ( ));
         }
         while (file2.hasNext ())
         {
             mergedFile.println (file2.nextLine ( ));
         }
         return mergedFile;
     }
     //Design a method to count the tokens in an existing and opened text file
     public static int countTokens (Scanner inFile)
     {
         int count = 0; String inString = "";
         while (inFile.hasNext ( ))
             inString += (inFile.nextLine ( ));
         int pos;
         while (true)
         {
             inString = inString.trim ( );
             pos = inString.indexOf (" ");
             if (pos == -1)
                 break;
             else
             {
                 count++;
                 inString = inString.substring (pos);
             }
         }
         return count;
     }
}

public class IndexOutOfRange extends Exception
{
    public IndexOutOfRange()
    {
        super ("array index out of bound");
    }

    public IndexOutOfRange (String msg)
    {
        super (msg);
    }
}

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