Book Image

Java 11 Cookbook - Second Edition

By : Nick Samoylov, Mohamed Sanaulla
Book Image

Java 11 Cookbook - Second Edition

By: Nick Samoylov, Mohamed Sanaulla

Overview of this book

For more than three decades, Java has been on the forefront of developing robust software that has helped versatile businesses meet their requirements. Being one of the most widely used programming languages in history, it’s imperative for Java developers to discover effective ways of using it in order to take full advantage of the power of the latest Java features. Java 11 Cookbook offers a range of software development solutions with simple and straightforward Java 11 code examples to help you build a modern software system. Starting with the installation of Java, each recipe addresses various problem by explaining the solution and offering insights into how it works. You’ll explore the new features added to Java 11 that will make your application modular, secure, and fast. The book contains recipes on functional programming, GUI programming, concurrent programming, and database programming in Java. You’ll also be taken through the new features introduced in JDK 18.3 and 18.9. By the end of this book, you’ll be equipped with the skills required to write robust, scalable, and optimal Java code effectively.
Table of Contents (18 chapters)

Running shell scripts


We generally collect a set of commands used in performing an operation in a file, called a shell script in the Unix world and a batch file in Windows. The commands present in these files are executed sequentially, with the exceptions being when you have conditional blocks or loops in the scripts. 

These shell scripts are evaluated by the shell in which they get executed. Different types of shells available are bash, csh, ksh, and so on. The bash shell is the most commonly used shell.

In this recipe, we will write a simple shell script and then invoke the same from the Java code using the ProcessBuilder and Process objects.

Getting ready

First, let's write our shell script. This script does the following:

  1. Prints the value of the environment variable, MY_VARIABLE
  2. Executes the tree command
  3. Executes the iostat command

Let's create a shell script file by the name, script.sh, with the following commands in it:

echo $MY_VARIABLE;
echo "Running tree command";
tree;
echo "Running iostat...