<section xml:id="drjava">

<title>Installing DrJava</title>

<p>

The easiest way to start programming in Java is to use a website that compiles and runs Java code in the browser.

Examples include \url{https://repl.it/}, \url{https://trinket.io/}, \url{https://jdoodle.com/}, and others.

</p>

<p>

If you are unable to install software on your computer (which is often the case in public schools and Internet caf&#xe9;s), you can use these online development environments for almost everything in this book.

</p>

<p>

But if you want to compile and run Java programs on your own computer, you will need the following:

<ul>

<li><p>The <em>Java Development Kit</em> (JDK), which includes the compiler, the <em>Java Virtual Machine</em> (JVM) that interprets the compiled byte code, and other tools such as Javadoc.

<idx><h>JDK</h></idx>

<idx><h>JVM</h></idx>

<idx><h>virtual machine</h></idx>

<idx><h>Javadoc</h></idx>

<idx><h>text editor</h></idx>

<idx><h>DrJava</h></idx></p></li>

<li><p>A <em>text editor</em> such as Atom, Notepad++, or Sublime Text, and/or an IDE such as DrJava, Eclipse, jGrasp, or NetBeans.</p></li>

</ul>

</p>

<p>

The JDK we recommend is OpenJDK, an open source implementation of Java<nbsp/>SE (Standard Edition).

The IDE we recommend is DrJava, which is an open source development environment written in Java (see <xref ref="fig_drjava1">Figure</xref>).

</p>

<p>

To install OpenJDK, visit \url{https://adoptopenjdk.net}.

Download and run the installer for your operating system.

</p>

<p>

<idx><h>JAR</h></idx>

To install DrJava, visit \url{http://drjava.org/} and download the <em>JAR</em> file.

We recommend that you save it to your <c>Desktop</c> folder or another convenient location.

Simply double-click the JAR file to run DrJava.

Refer to the DrJava documentation (\url{http://drjava.org/docs/quickstart/}) for more details.

</p>

<figure xml:id="fig_drjava1" >

<caption>DrJava editing the Hello World program.</caption>

<image width="95%" source="images/drjava-hello.png" />

</figure>

<p>

When running DrJava for the first time, we recommend you change three settings from the <em>Edit <m>></m> Preferences</em> menu under <em>Miscellaneous</em>: set the <em>Indent Level</em> to 4, check the <em>Automatically Close Block Comments</em> box, and uncheck the <em>Keep Emacs-style Backup Files</em> box.

</p>

</section>