Java Development Overview

When was the Java programming language developed and by whom? When was it introduced to the public?

Where does processing begin in a Java application?

What do you predict would be the result of the following line in a Java program: System.out.println("Hello");?

What do you predict would be the result of the following line in a Java program: //prints hello System.out.println("Hello");?

Which of the following are not valid Java identifiers? (Select all that apply)

Evaluate the following identifiers for a program: x, scoreSum, sumOfTheTestScoresOfTheStudents, smTstScr. Which is a good name to use?

What is white space? How does it affect program execution and readability?

What is Java bytecode?

What type of error is caused by misspelling a Java reserved word?

What occurs when calculating the average of an empty list of numbers?

What is described by printing a student's high test grade when the student's average test grade should have been output?

Java Development and Introduction

Developed in the early 1990s by James Gosling at Sun Microsystems.
Publicly introduced in 1995.

Java Application Processing

Processing starts with the main method in a Java application.

Standard Output in Java

Executing System.out.println("Hello"); prints "Hello" on the screen.
Comments, such as //prints hello, are ignored during execution, resulting in no output.

Valid Java Identifiers

Identifiers like RESULT, result, x1234y, and answer_7 are valid.
12345 and black&white are invalid identifiers due to starting with a digit and invalid character usage, respectively.

Identifier Naming Conventions

scoreSum is a good identifier name for representing test score sums.
Names like x, smTstScr may be less descriptive and therefore not as good.

White Space in Java

Refers to spaces, tabs, and newline characters that separate code elements.
Extra white space does not affect program execution but enhances human readability.

Java Bytecode

A low-level representation of Java source code generated by the Java compiler.
Bytecode can be executed by Java interpreters and may be transported over the web.

Types of Errors in Java

Compile-time error: Occurs from misspelling a Java reserved word.
Run-time error: Happens when performing operations like dividing zero by zero.
Logical error: Arises when incorrect output, such as printing a student's high score instead of the average, is produced.

This quiz covers essential concepts in Java development, including the origins of Java, application processing, valid identifiers, and naming conventions. Test your understanding of how Java processes code and the significance of whitespace in programming.