The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Dev.java for updated tutorials taking advantage of the latest releases.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.

Download and Try the Sample Application

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

1. Create a file named Count.java on your local computer by either copying or downloading the Count.java 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.
   
   

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   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.

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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.