Java™ Application Development on Linux - Dator

110Chapter 4Where Am I? Execution Contextso that args[0] 3 in the Java code to get the name of the file (see Section 4.2.1),but since we want to learn about properties, we’ll use the propertymethods here.Now let’s open that property file (Example 4.3).Example 4.3 Demonstrating the Properties classimport java.io.*;import java.util.*;public classEnvFileIn{public static voidmain(String [] args)throws IOException{String envfile = System.getProperty("ENVFILE", ".envfile");BufferedInputStream bis = new BufferedInputStream(new FileInputStream(envfile));Properties prop = new Properties();prop.load(bis);bis.close();prop.list(System.out); // dumps the whole list to System.out} // main} // class EnvFileInNotice the way that we got the value for the environment file’s name. Thisform of the getProperty() call provides not only the name we are lookingup (ENVFILE) but also lets us specify a default value in case the name is notfound in the properties list. Here our default value is .envfile.Just as it was a simple matter of using the load() method to read up anentire file of properties, so you can write out the entire list of properties to the3. In C language, the arg[0] is the command being invoked; not so in Java. In Java, the firstelement of the array is the first argument of the command line (propertyfile in ourexample).