This document introduces Java programming basics, covering binary, decimal, and hexadecimal number systems. It details the programming process, types of errors, console output differences, and method naming conventions. Additionally, it emphasizes procedural decomposition to manage coding tasks effectively.

1. Chapter 1: Intro to
Java Programming
AP Computer Science A
Building Java Programs, 3rd Edition

2. In this chapter:
Binary numbers
The basics of programming
Display console output
Creating your own methods

3. Binary
Numbers

4. Decimal Numbers
10 digits (0, 1, 2,
3, 4, 5, 6, 7, 8,
9)
Up by a power of
10 each place
value
Binary Numbers
2 digits (0, 1)
Up by a power
of 2 each
place value

5. Hexadecimal Numbers
16 digits (0, 1, 2, 3, 4, 5, 6, 7,
8, 9, A, B, C, D, E, F)
Up by a power of 16 each
place value

6. Decimal → Binary
45
= 32 + 8 + 4 + 2 + 1
32’s 16’s 8’s 4’s 2’s 1’s
1 0 1 1 0 1
= 101101

7. Binary → Decimal
10110
16 + 4 + 2
= 22
16’s 8’s 4’s 2’s 1’s
1 0 1 1 0

8. Powers of 2
0: 1
1: 2
2: 4
3: 8
4: 16
5: 32
6: 64
7: 128
8: 256
9: 512
10: 1024

9. Java
Programming
Basics

10. The Process of Programming
1. Write
Code 2. Compile
3. Execute4. Debug

11. The Process of Writing
1. Write
Draft
2. Proofread
3. Share4. Revise

12. Types of Errors
Syntax
Writing code
incorrectly
Caught by
compiler
Example: clas
HelloWorld
public
Logic (bugs)
Code doesn’t work
as expected
Example: displaying
what you didn’t
want displayed
Runtime
Program is stopped
Example: infinite
loop

13. Class Method Statement

15. Identifier Naming Conventions
Class names…
BeginWithACapitalLetter
AndCapitalizeEach
SuccessiveWord
Method names…
beginWithALowercase
letterandCapitalizeEach
successiveWord

16. Identifier Do’s and Don’ts
Do’s:
Contain:
Letters
Numbers
Underscores ( _ )
Dollar signs ( $ )
Examples:
HelloWorld numberOfSpaces
$$money$$ _________ o_O
CAPS_LOCK iHave$0
Don’ts:
Start with a number
Contain spaces
Contain any characters not
listed to the left
Examples:
2Dimensional 3DPoint
funkySymbols@#$% :) :(
^o^

17. Console
Output

18. println vs. print
println: Write on the next line when displaying
things again
print: Continue writing on the same line when
displaying things again

19. Escape Sequences
System.out.print("hello worldn");
=
System.out.print("hello world");
System.out.println();
Escape
Sequence
Meaning
" "
n new line
t tab
Input # of Spaces
Afterward
Result
"Merrittt" 1 "Merritt "
"Mulvaneyt" 0 "Mulvaney"
"Millhollent" 6 "Millhollen "

20. Comments
//these comments
//take up one line each
/*
This comment
can take up as many
lines as I want.
*/
/*
I'm writing a
comment
/*/ inside
of a comment!
*/
//I'm free to
//"quote whatever
//I want"!

22. Optional (for now) Knowledge
public: can be used in other programs
static: not involved in a specific object
void: no return value
main: default method
String[] args/String args[]: pass an array of Strings
as an argument
System: predefined class
out: a constant in the System class
println: a method that takes a String as a parameter

23. Making
Methods

24. Use method naming
conventions
Nothing in here
(for now)

25. Procedural Decomposition
Breaking up a large task into smaller
subtasks
For example: breaking up your code into
methods

30. public static void main(String[] args) {
egg();
}
public static void egg() {
System.out.println(" ______");
System.out.println(" / ");
System.out.println("/ ");
System.out.println(" /");
System.out.println(" ______/");
System.out.println();
teaCup();
}
public static void teaCup() {
System.out.println(" /");
System.out.println(" ______/");
System.out.println("+--------+");
System.out.println();
stopSign();
}
public static void stopSign() {
System.out.println(" ______");
System.out.println(" / ");
System.out.println("/ ");
System.out.println("| STOP |");
System.out.println(" /");
System.out.println(" ______/");
System.out.println();
hat();
}
public static void hat() {
System.out.println(" ______");
System.out.println(" / ");
System.out.println("/ ");
System.out.println("+--------+");
}

31. public static void toInfinityAndBeyond()
{
toInfinityAndBeyond();
}

32. Strategy
Keep the main method at the top
Write the next method right above the method
you just wrote