OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide

Exam 1Z0-815

Jeanne Boyarsky, Scott Selikoff

• Éditeur: Sybex
• Année: 2019
• ISBN:
  9781119584568
• Édition: 1
• Sujet: Computer Science
• Sous-sujet: Programming in Java

This OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide: Exam 1Z0-815 and the Programmer II Study Guide: Exam 1Z0-816 were published before Oracle announced major changes to its OCP certification program and the release of the new Developer 1Z0-819 exam. No matter the changes, rest assured both of the Programmer I and II Study Guidescover everything you need to prepare for and take Exam 1Z0-819. If you've purchased one of the Programmer Study Guides, purchase the other one and you'll be all set. NOTE: The OCP Java SE 11 Programmer I Exam 1Z0-815 and Programmer II Exam 1Z0-816 have been retired (as of October 1, 2020), and Oracle has released a new Developer Exam 1Z0-819 to replace the previous exams.The Upgrade Exam 1Z0-817 remains the same.

The comprehensive study aide for those preparing for the new Oracle Certified Professional Java SE Programmer I Exam 1Z0-815

Used primarily in mobile and desktop application development, Java is a platform-independent, object-oriented programming language. It is the principal language used in Android application development as well as a popular language for client-side cloud applications. Oracle has updated its Java Programmer certification tracks for Oracle Certified Professional.

OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide covers 100% of the exam objectives, ensuring that you are thoroughly prepared for this challenging certification exam. This comprehensive, in-depth study guide helps you develop the functional-programming knowledge required to pass the exam and earn certification. All vital topics are covered, including Java building blocks, operators and loops, String and StringBuilder, Array and ArrayList, and more. Included is access to Sybex's superior online interactive learning environment and test bank—containing self-assessment tests, chapter tests, bonus practice exam questions, electronic flashcards, and a searchable glossary of important terms. This indispensable guide:

• Clarifies complex material and strengthens your comprehension and retention of key topics
• Covers all exam objectives such as methods and encapsulation, exceptions, inheriting abstract classes and interfaces, and Java 8 Dates and Lambda Expressions
• Explains object-oriented design principles and patterns
• Helps you master the fundamentals of functional programming
• Enables you to create Java solutions applicable to real-world scenarios

There are over 9 millions developers using Java around the world, yet hiring managers face challenges filling open positions with qualified candidates. The OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide will help you take the next step in your career.

Chapter 1
Welcome to Java

OCP exam objectives covered in this chapter:

• 
  Understanding Java Technology and Environment
  • Describe Java Technology and the Java development environment
  • Identify key features of the Java language
• 
  Creating a Simple Java Program
  • Create an executable Java program with a main class
  • Compile and run a Java program from the command line
  • Create and import packages
• 
  Describing and Using Objects and Classes
  • Define the structure of a Java class

Welcome to the beginning of your journey to achieve a Java 11 certification. We assume this isn’t the first Java programming book you’ve read. Although we do talk about the basics, we do so only because we want to make sure you have all the terminology and detail you’ll need for the 1Z0-815 exam. If you’ve never written a Java program before, we recommend you pick up an introductory book on any version of Java. Examples include Head First Java, 2nd Edition (O’Reilly Media, 2009); Java for Dummies (For Dummies, 2017), Murach’s Java Programming (Murach, 2017), or Thinking in Java, 4th Edition (Prentice Hall, 2006). It’s okay if the book covers an older version of Java—even Java 1.3 is fine. Then come back to this certification study guide.

This chapter covers the fundamentals of Java. You’ll better understand the Java environments and benefits of Java. You’ll also see how to define and run a Java class and learn about packages.

Learning About the Java Environment

The Java environment consists of understanding a number of technologies. In the following sections, we will go over the key terms and acronyms you need to know for the exam and then discuss what software you need to study for the exam.

Major Components of Java

The Java Development Kit (JDK) contains the minimum software you need to do Java development. Key pieces include the compiler (javac), which converts .java files to .class files, and the launcher java, which creates the virtual machine and executes the program. We will use both later in this chapter when running programs at the command line. The JDK also contains other tools including the archiver (jar) command, which can package files together, and the API documentation (javadoc) command for generating documentation.

The javac program generates instructions in a special format that the java command can run called bytecode. Then java launches the Java Virtual Machine (JVM) before running the code. The JVM knows how to run bytecode on the actual machine it is on. You can think of the JVM as a special magic box on your machine that knows how to run your .class file.

Where Did the JRE Go?

In previous versions of Java, you could download a Java Runtime Environment (JRE) instead of the full JDK. The JRE was a subset of the JDK that was used for running a program but could not compile one. It was literally a subset. In fact, if you looked inside the directory structure of a JDK in older versions of Java, you would see a folder named jre.

In Java 11, the JRE is no longer available as a stand-alone download or a subdirectory of the JDK. People can use the full JDK when running a Java program. Alternatively, developers can supply an ...