Download and Try the Sample Application

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

  • 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.

  • 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.


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.

  • 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.