Trail: Essential Classes
Lesson: Exceptions
Questions and Exercises
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Questions and Exercises

Questions

  1. Is the following code legal?
    try {
        
    } finally {
        
    }
    
  2. What exception types can be caught by the following handler?
    catch (Exception e) {
         
    }
    
    What is wrong with using this type of exception handler?
  3. Is there anything wrong with the following exception handler as written? Will this code compile?
    try {
    
    } catch (Exception e) {
        
    } catch (ArithmeticException a) {
        
    }
    
  4. Match each situation in the first list with an item in the second list.
    1. int[] A;
      A[0] = 0;
    2. The JVM starts running your program, but the JVM can't find the Java platform classes. (The Java platform classes reside in classes.zip or rt.jar.)
    3. A program is reading a stream and reaches the end of stream marker.
    4. Before closing the stream and after reaching the end of stream marker, a program tries to read the stream again.
    1. __error
    2. __checked exception
    3. __compile error
    4. __no exception

    Exercises

    1. Add a readList method to ListOfNumbers.java. This method should read in int values from a file, print each value, and append them to the end of the vector. You should catch all appropriate errors. You will also need a text file containing numbers to read in.
    2. Modify the following cat method so that it will compile.
      public static void cat(File file) {
          RandomAccessFile input = null;
          String line = null;
      
          try {
              input = new RandomAccessFile(file, "r");
              while ((line = input.readLine()) != null) {
                  System.out.println(line);
              }
              return;
          } finally {
              if (input != null) {
                  input.close();
              }
          }
      }
      
    Check your answers.

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