Download and Try the Sample Application

This lesson uses a simple application that we provide to you.

  1. Create a file named on your local computer by either copying or downloading the source code. The examples in this lesson assume that you place count in the C:\Test directory.
  2. The count application needs to access a text file containing the data it will process. Download a sample data file, or use any other convenient text file as data.

    Important: Put your data file into a directory other than the directory containing your downloaded count class file. We suggest C:\TestData\data.

    Later in this lesson you will see how an application running under a security manager cannot read a file unless it has explicit permission to do so. However, an application can always read a file from the same directory (or a subdirectory). It does not need explicit permission.
  3. Compile and then run the Count application to see what it does.

    When you run the count application, you need to specify (as an argument) the path name of a file to be read.

    java Count C:\TestData\data

Here is a sample run:

    C:\Test>java Count C:\TestData\data
    Counted 65 chars.