Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The hallmark of a MapReduce system is this: map and reduce, the two primitives."

A block of code is set as follows:

<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.11</version>
  <scope>test</scope>
</dependency>

Any command-line input or output is written as follows:

./ec2/spark-ec2 -i ~/spark-keypair.pem launch myfirstsparkcluster --resume

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "From Spark 2.0.0 onwards, they have changed the packaging, so we have to include spark-2.0.0/assembly/target/scala-2.11/jars in Add External Jars…."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.