Introduction To Java (H2)

Question 1

A free-to-use, dynamic, high-level programming language for coding programs such as web apps, mobile apps, enterprise software, big data applications, and server-side technologies.

Answer 1

Java

Question 2

Who created Java and when?

Answer 2

Sun Microsystems in 1995. Which is now owned by oracle since june 23 2014

Question 3

What are the main features of Java?

Answer 3

Multi-platform, Object-Oriented, and network-centric; also considered a platform in itself.

Question 4

What are common uses of Java?

Answer 4

game development, cloud computing, big data, artificial intelligence (AI),
and Internet of Things

Question 5

Software that provides the class libraries and resources required for Java programs to run correctly.

Answer 5

Java Runtime Environment (JRE)

Question 6

What are 5 advantages of using Java?

Answer 6

1. Active community support
2. High-quality learning resources
3. Inbuilt functions and libraries
4. Strong security features
5. Platform independence (Write Once, Run Anywhere – WORA)

Question 7

A virtual machine and runtime engine that runs Java applications by translating Java bytecode into machine language.

Answer 7

JVM
Java Virtual Machine

Question 8

Natural programming languages fall
into two (2) broad categories:

Answer 8

Compilers and Interpreters.

Question 9

The program is written in natural English-like syntax with , and the language then translates the entire code into machine language. It converts the source code into a binary program of bytecode.

Answer 9

Compiler

Question 10

This checks the bytecode and communicates with the operating system, executing the bytecode instructions line by line

Answer 10

Interpreter

Question 11

What makes Java unique compared to other languages?

Answer 11

It was the first language to combine both compiling and interpreting using the Java Virtual Machine.

Question 12

What is the file extension of Java source code?

Answer 12

.java

Question 13

What is the program file name for the Java interpreter?

Answer 13

java.exe

Question 14

Pre-written Java programs that plug and play existing functionality into a code, such as getting the time and date, performing mathematical operations, or manipulating text.

Answer 14

Java APIs

Question 15

Give 3 examples of tasks Java APIs can perform.

Answer 15

Getting date/time, performing math operations, manipulating text.

Question 16

How many keywords does the Java language have?

Answer 16

Around 50.

Question 17

How many classes and methods does the Java API have?

Answer 17

Several thousands classes with thousands of methods.

Question 18

What is the basic unit of a Java program?

It also defines a group of objects that includes data members, which are places to store data, and methods which are places to put the program logic

Answer 18

A Class.

Question 19

The word ________ is the class name provided by the programmer.

Answer 19

Skeleton

Question 20

The name given to program components such as classes, objects, or variables.

Answer 20

Identifier

Question 21

What are the rules for naming identifiers?

Answer 21

Must begin with a letter, underscore (_), or dollar sign ($), not a digit.
Can contain letters, digits, underscores, or dollar signs, but no spaces.
Case-sensitive.
Cannot use true, false, or null.
Cannot use reserved words.

Question 22

Special words significant to the Java compiler. Aside from class names, these cannot be used as variables, a name used to refer to data stored in the memory.

Answer 22

Reserved Words (Keywords)

Question 23

What are the 3 reserved words in public static void main?

Answer 23

public → access modifier, required for main().
static → allows main() to run without creating an object.
void → indicates main() does not return a value.

Question 24

After the three (3) keywords is the name of the method.

Answer 24

Main

Question 25

What is the parameter of the main method?

Answer 25

String[] args → an array of strings (input arguments).

Question 26

In System.out.println("First Java Application"); what is System?

Answer 26

A class.

Question 27

What is out in the statement?

Answer 27

An object defined in the System class.

Question 28

What is println()?

Answer 28

A method used to print/display output.

Question 29

What is "First Java Application" in the statement?

Answer 29

A literal string (an argument passed to the method).

Question 30

What does every Java statement end with?

Answer 30

A semicolon (;).

Question 31

What symbol is used for single-line comments?

Answer 31

//brr brr patapim brr brr patapim **Forward slash**

Question 32

What symbols are used for multi-line comments?

Answer 32

/* skibidi bop bop dom yes yes Jejdndnn Ndjjdj Jdjdjj Jrjdjjd */

Question 33

includes complete JRE tools for developing, debugging, and monitoring Java applications. This must be installed on the computer to write, compile, and execute Java programs.

Answer 33

Java Development Kit (JDK).

Question 34

What command is used to compile a Java program?

Answer 34

javac [filename].java

Question 35

What command is used to run a Java program?

Answer 35

java [filename] (without .java).

Question 36

What are the steps to save and run a Java program in CMD?

Answer 36

1. Write code in a text editor and save as .java file. 2. Open CMD and change to directory where file is saved. 3. Set JDK path using set path=%path%;[JDK bin directory]. 4. Compile using javac filename.java. 5. Execute using java filename.

Question 37

What analogy is used to describe a class in Java?

Answer 37

A class is like a blueprint for a house, while the object is the actual house built from that blueprint.

Question 38

Where must the whole definition of the Skeleton class be written?

Answer 38

Between the first opening brace { and the last closing brace }.

Question 39

Which primitive values cannot be used as identifiers in Java?

Answer 39

true, false, and null (they are not reserved keywords. They are **Primitive Values**).

Question 40

important software components bundled with the Java Platform.

Answer 40

API (Application Programming Interface)

Question 41

A class name is a type of an ________

Answer 41

Identifier

Question 42

A name used to refer to data stored in the memory.

Answer 42

Variable

Question 43

On line 1, _ are used to identify blocks of code and data. It requires matching opening "**{**"and closing _ "**}**". Thus, the whole definition of the class **Skeleton** should be **between the first opening _** and the **last closing _** on line 5.

Answer 43

Braces → { }

Question 44

A type of **access or visibility modifier**. This keyword is used to **define a main()** method so that the interpreter can execute the program.

Answer 44

Public

Question 45

**tells** that this is a class method. The main method is always declared _ so that it can be executed **without creating an object of the class**.

Answer 45

Static

Question 46

Means that the main is a **non-value-returning** method, which means the main is not expected to return any value.

Answer 46

Void

Question 47

**Inside** the **parentheses after the method name**, _ are listed along with their types to **allow the method to receive values**.

Answer 47

Parameters

Question 48

The main method has a **parameter** called _, an array of type **String**, and the square brackets **[ ]** indicate _, is an array

Answer 48

Args

Question 49

Collection of **similar data types**

Answer 49

Array

Question 50

**Sequence of characters** containing letters, numbers, and symbols.

Answer 50

String

Question 51

A sample program to be saved, compiled, and executed using the **command prompt (CMD)**: What step is this? Write the following code in a text editor such as Notepad (or any text editor.)

Answer 51

Step 1

Question 52

A sample program to be saved, compiled, and executed using the **command prompt (CMD)**: What step is this? If using a Notepad as an editor to write a program, the file must be saved with double quotes (","). Otherwise, it automatically adds a .txt extension. The sample program above should be saved as "Demo.java".

Answer 52

Step 2

Question 53

A sample program to be saved, compiled, and executed using the **command prompt (CMD)**: What step is this: Open the DOS window (cmd), then change the directory to the directory where the Java file was saved.

Answer 53

Step 3

Question 54

A sample program to be saved, compiled, and executed using the **command prompt (CMD)**: What step is this? Set the path of JDK using the path command. This setting tells the operating system where to find the Java compiler and the classes. Setting the path of JDK is defined as set path=%path%;[JDK bin directory]

Answer 54

Step 4

Question 55

A sample program to be saved, compiled, and executed using the **command prompt (CMD)**: What step is this? Compile the Java program using the javac command: javac [name of the Java file].java

Answer 55

Step 5

Question 56

A sample program to be saved, compiled, and executed using the **command prompt (CMD)**: What step is this? Execute the compiled Java program using the **java command** (interpreter): **java [name of the Java file]**

Answer 56

Step 6

Question 57

Java code can be written once and run on any underlying platform like Windows, iOS, Android, and Linux without rewriting. This feature is called the _ Philosophy which became a highly sought feature by developers.

Answer 57

“Write Once, Run Anywhere” (WORA)

Question 58

Separate classes, objects, and methods

Answer 58

Dots

Question 59

Java is used for coding:

Answer 59

programs such as **web** applications, **mobile** applications, **enterprise** software, **big data** applications, and **server-side tech**nologies.

Question 60

The programming statements or source code are stored on a disk with a

Answer 60

*.java* file extension

Question 61

All Java applications **must include a class containing one** (1) _ method.

Answer 61

Main

Question 62

When executing a Java program, the execution must **always begin** with the _ method.

Answer 62

Main