Skip to main content\(
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\definecolor{fillinmathshade}{gray}{0.9}
\newcommand{\fillinmath}[1]{\mathchoice{\colorbox{fillinmathshade}{$\displaystyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\textstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptscriptstyle\phantom{\,#1\,}$}}}
\)
Section 2.2 Summary & Reading Questions
-
Java programs must be compiled before execution, unlike Python which is interpreted directly.
-
Every Java program must define a
class, and all code must be inside that class.
-
Each Java program must include a
public static void main(String[] args) method as the entry point.
-
Java enforces that every variable and method must have a clearly defined type, including
void for methods that return nothing.
-
Statements in Java must end with a semicolon (
;), and whitespace is not syntactically meaningful.
-
Java uses dot notation to access class members, such as
System.out.println for output.
-
The
static keyword indicates that a method belongs to the class itself, rather than to an instance of the class.
Reading Questions Reading Questions
1.
Which of the following must be true of every Java program?
-
It must contain a method called main() with no parameters.
-
No. The main method must include a specific parameter: String[] args.
-
It must include a public static void main(String[] args) method inside a class.
-
Correct! This is the required entry point for all Java applications.
-
It must be saved with a .exe extension.
-
No. Java source files use the .java extension and compile to .class.
-
It must be run using the Python interpreter.
-
No. Java uses its own compiler and Java Virtual Machine (JVM).
2.
What is the purpose of the
javac command?
-
To compile Java source code into bytecode
-
Exactly! javac compiles .java files into .class files.
-
To run a Python program
-
No. Python programs are run with the python or python3 command.
-
To debug Java programs
-
No. javac only compiles code. Debugging is a separate process.
-
To edit Java source files
-
No. You use a text editor or IDE to edit Java files.
3.
What symbol does Java use to indicate the end of a statement?
-
#
-
No. # is used for comments in Python, not for statement termination.
-
;
-
Correct! Java uses semicolons to mark the end of a statement.
-
.
-
No. . is used for dot notation, not to end a statement.
-
}
-
No. } is used to close code blocks.
4.
Construct a complete Java program that prints your name and your favorite color to the console. Drag the blocks into the correct order on the right.
public class NameColor {
---
class NameColor {
#paired
---
public static void main(String[] args) {
---
public static main(String[] args) {
#paired
---
System.out.println("Name: Alex");
System.out.println("Favorite Color: Blue");
---
system.out.println(Name: Alex);
System.out.println("Favorite Color: Blue")
#paired
---
}
}
You have attempted
of
activities on this page.
