Topic 1.3: Java Basics - Create executable Java applications with a main method; run a Java program from the command line; produce console output

Question 1

this format flag adds grouping separators to numeric values.

Answer 1

How does the format flag “,” affect numeric values in printf()?

Question 2

This is part of Java Runtime Environment (JRE) and is Responsible for executing Java bytecode.

it achieves this by interpreting and translating bytcode into machine-specific instructions.

Answer 2

define and note the role of the
Java Virtual Machine (JVM)

Question 3

The console output methods belong to the PrintStream class.

Answer 3

Which class do the console output methods belong to?

Question 4

How does the format flag “-“ affect the output in printf()?

Answer 4

This format flag left-justifies the value within the specified width

Question 5

How can
console output
be performed in Java?

Answer 5

this can be performed using the out field of the System class (System.out). which is an instance of the PrintStream class

Question 6

This format flag left-justifies the value within the specified width

Answer 6

How does the format flag “-“ affect the output in printf()?

Question 7

In what order should elements of the format specifiers be used in printf()?

Answer 7

The order for these is

%[flags][width][precision][specifier]

Question 8

This determines the number of digits after the decimal point for floating-point numbers.

Note:
rounding upwards will occur

Answer 8

What is the purpose of precision in printf()?

Question 9

An executable Java application is a program that can be executed independently.

A requirement for this is that we define a class with a special method called the main method. the main method will then act as the entry point for the program execution

Answer 9

What is a requirement for creating an executable java application

Question 10

What is the purpose of the width specifier in printf()?

Answer 10

this specifies the minimum number of characters to be printed for the corresponding value.

Question 11

define the
Java Runtime Environment (JRE)
and note some of its components

Answer 11

This Consists of files and components necessary for running Java applications at runtime.

Notable components include:
* Java Virtual Machine (JVM): Executes Java bytecode.
* Standard Java class libraries: Collection of pre-defined classes and APIs.
* Runtime components: Additional tools and resources required for execution.

Question 12

the syntax / usage of this is using a period (.) followed by a positive integer after the width specifier.

Answer 12

What is the syntax for specifying precision in printf()?

Question 13

How can you specify the width of the output in printf()?

Answer 13

The width is specified as a positive integer between the % symbol and the format specifier.

Question 14

The printf() method is used to create formatted strings by replacing format specifiers with values.

Answer 14

What is the purpose of the printf() method?

Question 15

This is a software development kit provided by Oracle Corporation for developing, compiling, and running Java applications.

Notable components include:
* Java Compiler (javac): Used to compile Java source code into bytecode.
* Java Runtime Environment (JRE): Includes the JVM (java) and necessary runtime components for running Java applications.
* Development Tools: Various tools for Java development, such as debugger, profiler, and documentation generator.

Answer 15

define the
Java Development Kit (JDK)
and note some of its components

Question 16

Step: Compile the source code using the Java compiler (javac).

Command: javac YourClass.java

Output: Creates a .class file containing the bytecode.

Answer 16

what is the

• first step
• command
• output

of Running a Java Program from the Command Line

Question 17

What are some common format specifiers in printf()?

Answer 17

Common format specifiers include:
* %s (string),
* %d (integer),
* %f (floating-point),
* %c (character),
* and %b (boolean).

Question 18

What is the purpose of the printf() method?

Answer 18

The printf() method is used to create formatted strings by replacing format specifiers with values.

Question 19

Format flags change the behavior of the format specifier and are set using a single character preceded by the % symbol

Answer 19

What is a format flag in printf()?

Question 20

what is the output of

System.out.printf("%.3f", 1.23456789);

Answer 20

Output: 1.235

Question 21

what is the
header of the main method

Answer 21

the header for this is:

public static void main(String[] args)

Question 22

What does the format flag “(“ do in printf()?

Answer 22

This format flag encloses negative numbers within parentheses.

Question 23

what is the output of

System.out.printf("|%-10s|", "Hello");

Answer 23

Output: |Hello |

Question 24

what is the output of

System.out.printf("%(.2f", -3.14);

Answer 24

Output: (3.14)

Question 25

The order for these is

%[flags][width][precision][specifier]

Answer 25

In what order should elements of the format specifiers be used in printf()?

Question 26

This format flag pads numeric values with leading zeros instead of spaces. note that a length must be given and the “-“ flag may not be used

Answer 26

What is the purpose of the format flag “0” in printf()?

Question 27

what is the

• second step
• command
• output

of Running a Java Program from the Command Line

Answer 27

Step: Execute the bytecode using the Java Virtual Machine (JVM) and runtime environment.
Command: java YourClass (extension is not required)
Output: JVM starts the execution and searches for the main method in YourClass. The main method in YourClass is executed, and the program starts running

Question 28

This format flag encloses negative numbers within parentheses.

Answer 28

What does the format flag “(“ do in printf()?

Question 29

What is the difference between the println() and print() methods?

Answer 29

The println() method adds a new line character at the end of the text, while the print() method does not automatically add a new line character.

Question 30

The println() method adds a new line character at the end of the text, while the print() method does not automatically add a new line character.

Answer 30

What is the difference between the println() and print() methods?

Question 31

Common format specifiers include:
* %s (string),
* %d (integer),
* %f (floating-point),
* %c (character),
* and %b (boolean).

Answer 31

What are some common format specifiers in printf()?

Question 32

What is the purpose of the format flag “0” in printf()?

Answer 32

This format flag pads numeric values with leading zeros instead of spaces. note that a length must be given and the “-“ flag may not be used

Question 33

what is the

• first step
• command
• output

of Running a Java Program from the Command Line

Answer 33

Step: Compile the source code using the Java compiler (javac).

Command: javac YourClass.java

Output: Creates a .class file containing the bytecode.

Question 34

What does precision refer to in printf()?

Answer 34

Precision applies to floating-point numbers and determines the number of digits after the decimal point.

Question 35

what is the output of
System.out.printf("%+d", 42);

Answer 35

Output: +42

Question 36

what is the output of

System.out.printf("%,d", 1000000);

Answer 36

Output: 1,000,000

Question 37

The width is specified as a positive integer between the % symbol and the format specifier.

Answer 37

How can you specify the width of the output in printf()?

Question 38

What does the format flag “+” do in printf()?

Answer 38

This format flag includes a sign (+ or -) for numeric values.

Question 39

This Consists of files and components necessary for running Java applications at runtime.

Notable components include:
* Java Virtual Machine (JVM): Executes Java bytecode.
* Standard Java class libraries: Collection of pre-defined classes and APIs.
* Runtime components: Additional tools and resources required for execution.

Answer 39

define the
Java Runtime Environment (JRE)
and note some of its components

Question 40

this can be performed using the out field of the System class (System.out). which is an instance of the PrintStream class

Answer 40

How can
console output
be performed in Java?

Question 41

define the
Java Development Kit (JDK)
and note some of its components

Answer 41

This is a software development kit provided by Oracle Corporation for developing, compiling, and running Java applications.

Notable components include:
* Java Compiler (javac): Used to compile Java source code into bytecode.
* Java Runtime Environment (JRE): Includes the JVM (java) and necessary runtime components for running Java applications.
* Development Tools: Various tools for Java development, such as debugger, profiler, and documentation generator.

Question 42

Step: Execute the bytecode using the Java Virtual Machine (JVM) and runtime environment.
Command: java YourClass (extension is not required)
Output: JVM starts the execution and searches for the main method in YourClass. The main method in YourClass is executed, and the program starts running

Answer 42

what is the

• second step
• command
• output

of Running a Java Program from the Command Line

Question 43

This format flag includes a sign (+ or -) for numeric values.

Answer 43

What does the format flag “+” do in printf()?

Question 44

define and note the role of the
Java Virtual Machine (JVM)

Answer 44

This is part of Java Runtime Environment (JRE) and is Responsible for executing Java bytecode.

it achieves this by interpreting and translating bytcode into machine-specific instructions.

Question 45

What is the syntax for specifying precision in printf()?

Answer 45

the syntax / usage of this is using a period (.) followed by a positive integer after the width specifier.

Question 46

What is the purpose of precision in printf()?

Answer 46

This determines the number of digits after the decimal point for floating-point numbers.

Note:
rounding upwards will occur

Question 47

How does the format flag “,” affect numeric values in printf()?

Answer 47

this format flag adds grouping separators to numeric values.

Question 48

What is a format flag in printf()?

Answer 48

Format flags change the behavior of the format specifier and are set using a single character preceded by the % symbol

Question 49

what is the output of
System.out.printf("%08d", 42);

Answer 49

Output: 00000042

Question 50

Precision applies to floating-point numbers and determines the number of digits after the decimal point.

Answer 50

What does precision refer to in printf()?

Question 51

the header for this is:

public static void main(String[] args)

Answer 51

what is the
header of the main method

Question 52

What is a requirement for creating an executable java application

Answer 52

An executable Java application is a program that can be executed independently.

A requirement for this is that we define a class with a special method called the main method. the main method will then act as the entry point for the program execution

Question 53

this specifies the minimum number of characters to be printed for the corresponding value.

Answer 53

What is the purpose of the width specifier in printf()?

Question 54

Which class do the console output methods belong to?

Answer 54

The console output methods belong to the PrintStream class.