When somebody says "Java," they may mean quite different things:

• Java programming language: A high-level programming language that allows an intent (a program) to be expressed in a human-readable format that can be translated in the binary code executable by a computer
• Java compiler: A program that can read a text written in the Java programming language and translate it into a bytecode that can be interpreted by Java Virtual Machine (JVM) in the binary code executable by a computer
• Java Virtual Machine (JVM): A program that reads a compiled Java program and interprets it into the binary code that is executable by a computer
• Java Development Kit (JDK): The collection of programs (tools and utilities), including Java compiler, JVM, and supporting libraries, which allow the compilation and execution of a program written in the Java language...

What used to be just a specialized editor that allowed checking the syntax of the written program the same way a Word editor checks the syntax of an English sentence gradually evolved into an Integrated Development Environment (IDE). This bears its main function in the name. It integrates all the tools necessary for writing, compiling, and then executing a program under one Graphical User Interface (GUI). Using the power of Java Compiler, the IDE identifies syntax errors immediately and then helps to improve code quality by providing context-dependent help and suggestions.

There are several IDEs available for a Java programmer, such as NetBeans, Eclipse, IntelliJ IDEA, BlueJ...

With all the main programming tools in place, we can start talking about Java as a language. The language syntax is defined by Java Language Specification, which you can find on https://docs.oracle.com/javase/specs. Don't hesitate to refer to it every time you need some clarification. It is not as daunting as many people assume.

All the values in Java are divided into two categories: reference types and primitive types. We start with primitive types and operators as the natural entry point to any programming language. In this chapter, we will also discuss one reference type called String (see the String type and literals section).

All primitive types can be divided into two groups: the boolean type and the numeric types.

We have just described the primitive value types of the Java language. All the other value types in Java belong to a category of reference types. Each reference type is a more complex construct than just a value. It is described by a class, which serves as a template for creating an object, a memory area that contains the values and methods (the processing code) defined in the class. An object is created by the new operator. We will talk about classes and objects in more detail in Chapter 2, Java Object-Oriented Programming (OOP).

In this chapter, we will talk about one of the reference types called String. It is represented by the java.lang.String class, which belongs, as you can see, to the most foundational package of JDK, java.lang. The reason we introduce the String class that early is that it behaves in some respects very similar to primitive types...

From our school days, we have an intuitive understanding of what a variable is. We think of it as a name that represents a value. We solve problems using such variables as x gallons of water or n miles of a distance, and similar. In Java, the name of a variable is called an identifier and can be constructed by certain rules. Using an identifier, a variable can be declared (defined) and initialized.

According to Java Language Specification (https://docs.oracle.com/javase/specs), an identifier (a variable name) can be a sequence of Unicode characters that represent letters, digits 0-9, a dollar sign ($), or an underscore (_).

Other limitations are as follows:

• The first symbol of an identifier...

A Java statement is a minimal construct that can be executed. It describes an action and ends with a semicolon (;). We have seen many statements already. For example, here are three statements:

float f = 23.42f;
String sf = String.valueOf(f);
System.out.println(sf);

The first line is a declaration statement combined with an assignment statement. The second line is also a declaration statement combined with an assignment statement and method invocation statement. The third line is just a method invocation statement.

Here is the list of Java statement types:

• An empty statement that consists of only one symbol, ; (semicolon)
• A class or interface declaration statement (we will talk about this in Chapter 2, Java Object-Oriented Programming (OOP))
• A local variable declaration statement: int x;
• A synchronized statement: this is beyond the scope of this book
• An expression...

This chapter introduced you to the exciting world of Java programming. We started with explaining the main terms, and then explained how to install the necessary tools, JDK and IDE, and how to configure and use them.

With a development environment in place, we provided the reader with the basics of Java as a programming language. We have described Java primitive types, the String type, and their literals. We have also defined what an identifier is, and what a variable is, and finished with a description of the main types of Java statements. All the points of the discussion were illustrated by the specific code examples.

In the next chapter, we are going to talk about the object-oriented aspects of Java. We will introduce the main concepts, explain what a class is, what an interface is, and the relationship between them. The terms overloading, overriding, and hiding will...

1. What does JDK stand for?

• 1. Java Document Kronos
  2. June Development Karate
  3. Java Development Kit
  4. Java Developer Kit

2. What does JCL stand for?

• 1. Java Classical Library
  2. Java Class Library
  3. Junior Classical Liberty
  4. Java Class Libras

3. What does Java SE stand for?

• 1. Java Senior Edition
  2. Java Star Edition
  3. Java Structural Elections
  4. Java Standard Edition

4. What does IDE stand for?

• 1. Initial Development Edition
  2. Integrated Development Environment
  3. International Development Edition
  4. Integrated Development Edition

5. What are Maven's functions?

• 1. Project building
  2. Project configuration
  3. Project documentation
  4. Project cancellation

6. What are Java primitive types?

• 1. boolean
  2. numeric
  3. integer
  4. string

7. What are Java primitive types?

• 1. long
  2. bit
  3. short
  4. byte

8. What is a literal?

• 1. A letter-based string
  2. A number-based string
  3. A variable representation
  4. A value representation...