This document contains code snippets and explanations related to Java programming concepts like classes, objects, methods, conditionals, loops, and arrays. It begins with simple examples of printing text and using methods. It then covers more complex topics like defining classes with fields and methods, if/else and switch conditional statements, for, while, and do-while loops, parsing user input, and creating and accessing objects. The document appears to be notes or exercises for learning Java programming fundamentals through worked examples and explanations.

1. 1

2. 2

3. 3

4. 4

5. SEMESTRAL PLANS

7. WEEKLY PLANS

8. •
•
•
•
•
• • ✓
✓
✓
✓
•
•
• • •
•
✓
✓
✓

9. ✓
•
•
•
•
•
•
•
• • ✓
✓
✓
✓
• • • • ✓
✓

10. •
•
• • ✓
✓
✓
•
•
•
• • • ✓
✓
✓
✓
• • • • ✓

11. •
•
• ✓
✓
✓
•
•
• •
•
•
•
✓
✓
✓
✓
• • • • ✓

12. •
•
•
•
•
•
✓
✓
✓
•
•
•
•
•
•
• •
•
✓
✓
✓
✓
• • • • ✓
✓

13. •
• •
•
• ✓
✓
•
•
•
•
•
•
•
•

15. •
•
•
•
•
•

16. Part 1.
public class Exercise1
{
public static void main(String[] args)
{
System.out.println("Correct!");
}
}

17. Part 2. (Total: 17 items)
Class cell phone Object
brand
model
LCD size
weight
dimensions/size
talk time
battery standby time
Nokia
Nokia n70
176 x 208 pixels
125 grams
109 x 53 x 24 mm
3.5 hours
11 days
Send_Message Call
Take_Picture Record_Video

21. •
•
•
•
•
•
•
•
•
•
•
System.out.print();
System.out.println();

22. printWelcome()

23. public class Exercise2
{
public static void mail(String[] args)
{
System.out.print("+++++++++");
System.out.println("+++++++++");
System.out;println("++ ++")'
System.out.println("++ ++");
System.out.println("+++++++++")>
System.oul.printtn("+++++++++");
}
}

24. System.out.println() System.out.print()
System.out.print()
System.out.println()
public class Exercise2
{
public static void main(String[] args)
{
System.out.println("+++++++++");
System.out.println("+++++++++");
System.out.println("++ ++");
System.out.println("++ ++");
System.out.println("+++++++++");
System.out.println("+++++++++");
}
}
public class Lesson2
{
public static void main(String[] args)
{
System.out.println("The quick brown fox jumped over
the");
System.out.println("lazy dog and ran through the
forest.");
System.out.println(" ");
System.out.println(" ___ /");
System.out.println(" ^ ^ ");
System.out.println(" o / ");
System.out.println("Fox");
}
}

25. System.out.print()
System.out.println("HelloEveryone!!!");
"Hello Everyone!!!" ""Hello Everyone!!!""

26. public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World");
}
}

28. ** *** ********** ** * **
** *** ** ** ** *** **
** *** ** ** ** ** ** **
** *** ** ** ** ** ** **
***** ** ** ** ** ** **
** *** ** ** ** ** ** **
** *** ** ** ** ** ** **
** *** ** ** *** ***
** *** ********** * *

30. •
•
•
•
•
•
•
•
•

32. public class Lesson3
{
public static void main(String[] args)
{
final double d = 10.8;
final boolean b = false;
final String s1 = "quick brown fox";
final String s2 = "slow yellow fox";
final int i = 4;
System.out.println(d);
System.out.println(b);
System.out.println(s1 + " and " + s2);
System.out.println(i);
System.out.println((int)d - i);
}
}
public class Exercise3
{
public static void main(String[] args)
{
final double d = 5.5;
final String s1 = "tekki";
final int i = 4;
System.out.println(d);
System.out.println(s1 + " is cool!");
System.out.println(i);
System.out.println((int)d - i);
}
}

33. Average = (int)((Quiz_1+Quiz_2)/2); //explicit casting
int
System.out.println((int)d);

35. •
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

37. •
•
•
•
•
•
•

39. public class Exercise4
{
public static void main(String[] args)
{
final int A = 1, B = 0;
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.println(A);
System.out.print(A);
System.out.print(" ");
System.out.println(A);
System.out.print(A);
System.out.print(" ");
System.out.print(B);
System.out.print(" ");
System.out.print(B);
System.out.print(" ");
System.out.println(A);
System.out.print(A);
System.out.print(" ");
System.out.println(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.print(A);
System.out.println(A);
}
}

40. Part 2.
final int Y = 10, Z = 20;
System.out.println(Z/Y); //to print out “2”
System.out.println(Z+Y); //to print out “30”
System.out.println(Z-Y-Y); //to print out “0”
System.out.println(Z>Y); //to print out “true”
final int Y = 10, Z = 20;
System.out.println(2); //to print out “2”
System.out.println(30); //to print out “30”
System.out.println(0); //to print out “0”
System.out.println(true); //to print out “true”
public class Lesson4
{
public static void main(String[] args)
{
final int A = 3, B = 10;
System.out.println(A+A+A+B); // can be different
System.out.println(A-B);// can be different
System.out.println(A*B);// can be different
System.out.println(B/(A/A));// can be different
System.out.println(B%A);
System.out.println(A>B);// can be different
System.out.println(A<B);// can be different
}
}

42. Operator Description Example
= assigns values from right side operands to left side operands a=b
+= adds right operand to the left operand and assigns the result
to left
a+=b is same as a=a+b
-= subtracts the right operand from the left operand and assigns
the result to left operand
a-=b is same as a=a-b
*= multiplies the left operand by the right operand and assigns
the result to the left operand
a*=b is same as a=a*b
/= divides the left operand by the right operand and assigns the
result to the left operand
a/=b is same as a=a/b
%= calculates the modulus using two operands and assigns the
result to the left operand
a%=b is same as a=a%b
Operator Description
& Bitwise AND
| Bitwise OR
^ Bitwise exclusive OR
<< left shift
>> right shift

43. if-else
if-else

44. •
•
•
•
•
•
if switch
if switch
switch

46. public class Exercise5
{
public static void main(String[] args){
int x = 0;
System.out.println("Value is: " + x);
if(x%2 == 0)
{
System.out.println("Even!");
} else {
System.out.println("Out!");
}
}
}

47. public class Lesson5
{
public static void main(String[] args)
{
final double NUMBER = 24.18;
int flag = 0;
System.out.print("Initial value of flag is: ");
System.out.println(flag);
System.out.print("Initial value of NUMBER is: ");
System.out.println(NUMBER);
if(NUMBER > 0)
flag = 1;
else
if(NUMBER < 0)
flag = 2;
else
flag = 0;
switch(flag)
{
case 1: System.out.println("NUMBER is POSITIVE.");
break;
case 2: System.out.println("NUMBER is NEGATIVE.");
break;
case 0: System.out.println("NUMBER is ZERO!");
break;
}
System.out.print("Final value of flag is: ");
System.out.println(flag);
System.out.print("Final value of NUMBER is: ");
System.out.println(NUMBER);
}
}

48. 1. if (a == 5) {
b += 3;
} else {
if (b > 4) {
c = 3;
}
2. if (a == 0) {
b = 1;
} else {
if (a == 1) {
b = 0;
} else {
b = -1;
}
}
3. if (a == 2) {
b = 10;
} else {
b = 35;
}
c = true;
1. switch (sides) {
case 3: polygon = "Triangle"; break;
case 4: polygon = "Quadrilateral"; break;
case 5: polygon = "Pentagon"; break;
case 6: polygon = "Hexagon"; break;
case 7: polygon = "Heptagon"; break;
case 8: polygon = "Octagon"; break;
case 9: polygon = "Nonagon"; break;
case 10: polygon = "Decagon"; break;
}

49. 2. switch (answer) {
case ‘A’:
case ‘a’:
points+=100;
break;
case ‘B’:
case ‘b’:
points+=200;
break;
case ‘C’:
case ‘c’:
points-=100;
break;
default:
points -= 200;
}

54. •
•
•
•
•
•
•
for
while
do-while

55. for
while do-while
Are we
there
yet?
Condition
If no,
Repeat
If yes,
Halt Loop
Walk

57. public class Exercise6
{
public static void main(String[] args){
for(int i = 1; i < 10; i++){
System.out.print(i);
System.out.print(" ");
}
}
}
public class Lesson6
{ public static void main(String[] args)
{ int counter = 0;
for(counter = 1; counter<=20; counter++)
{ System.out.print(counter * 4+ " ");
if(counter%5==0)
System.out.println();
}
}
}
System.out.print(counter * 3+ " ");
if(counter%10==0)
System.out.println();

58. (int counter = 5; counter >=0 ;counter--) {
System.out.println(counter);
}

59. continue;

60. *******
******
*****
****
***
**
*

61. 1******
12*****
123****
1234***
12345**
123456*
1234567

63. •
•
•
•
•

65. import java.io.*;
public class Exercise7
{
public static void main(String[] args)
{
BufferedReader dataIn=new BufferedReader(new
InputStreamReader(System.in));
int x = 0;
x = 10;
if(x%2==0)
System.out.println("Multiple of 2");
else
System.out.println("NOT a multiple of 2");
}
}

66. if(x%2==0)
System.out.println("Even number");
else
System.out.println("Odd number");
import java.io.*;
public class Lesson7
{
public static void main(String[] args)
{
BufferedReader dataIn=new BufferedReader(new
InputStreamReader(System.in));
int x = 0;
String Str_1;
System.out.print("Enter an integer value: ");
try
{
Str_1=dataIn.readLine();
x=Integer.parseInt(Str_1);
}
catch(Exception e)
{
System.out.println("Error reported");
}
if(x%5==0)
System.out.println("Number is a multiple of 5.");
else
System.out.println("Number is NOT a multiple of 5");
}
}

71. •
•
•
•
•
•
•
•
•
•
•

73. public class Exercise8
{
public static void main(String[] args){
AccessMe access = new AccessMe();
System.out.println(access.printme());
}
}

74. public class DRINKCONTAINER
{
private String BRAND, COLOR;
private final double CAPACITY = 10.0;
public double AMOUNTCONTAINED = 0.0;
public double getContents()
{
return AMOUNTCONTAINED;
}
public String getBrand()
{
return BRAND;
}
public String getColor()
{
return COLOR;
}
public void setBrand(String str)
{
BRAND = str;
}
public void setColor(String str)
{
COLOR = str;
}
public void throwContents()
{
AMOUNTCONTAINED = 0;
}
public void addContents(double x)
{
double temp;
temp = AMOUNTCONTAINED + x;
if(temp>=CAPACITY)
{
System.out.println("Maximum Capacity reached.");
AMOUNTCONTAINED = CAPACITY;
}
else
{
AMOUNTCONTAINED = temp;
}
}
}
BRAND and COLOR
as String
CAPACITY in liters
(final double) = 10.0
AMOUNTCONTAINE
D (a double that will
tell how many liters is
already inside a
DRINKCONTAINER
object) that should not
getContents() –
returns
AMOUNTCONTAIN
getColor() – returns
COLOR
setBrand(String str) –
sets the value of
BRAND equal to str
setColor(String str) –
sets the value of
COLOR equal to str
throwContent
s() – sets
AMOUNTCO
NTAINED to
0
addContents(double x) – adds
the argument passed to the
value of
AMOUNTCONTAINED. Again,
AMOUNTCONTAINED should
not exceed CAPACITY
getBrand() – returns
BRAND

75. public class Container_Controller {
public static void main(String[] args) {
DRINKCONTAINER dc= new DRINKCONTAINER();
System.out.println("Setting container color to
black."); dc.setColor("BLACK");
System.out.println("Setting brand to BRAND X.");
dc.setBrand("BRAND X");
System.out.println("Adding 9 liters of content..");
dc.addContents(9);
System.out.println("Adding 2 liters of content..");
dc.addContents(2);
System.out.println("Adding half liter of
content.."); dc.addContents(9);
System.out.println("CONTAINER DETAILS: ");
System.out.println("color: "+dc.getColor());
System.out.println("brand: "+dc.getBrand());
System.out.println("contents: "+dc.getContents() + "
liters");
System.out.println("Emptying container...");
dc.throwContents();
System.out.println("Container contents:
"+dc.getContents() + " liters");
}
}
dc.setColor("BLACK"); //
dc.setBrand("BRAND X"); //
dc.addContents(9); //

76. dc.addContents(2); //
// 10.0,
// 10.0 “spilt”
// 10.0
dc.addContents(9); //

78. •
•
•
•
•
public class Puppy{
public Puppy(){
}
public Puppy(String name){
// This constructor has one parameter, name.
}
}

81. •
•
•
•
•
•

82. int [] INTARRAY=new int [30];
int i;
double DOUBLEAVERAGE = 0.0;
double [] DOUBLEARRAY=new double [30];

83. INTARRAY
DOUBLEAVERAGE
DOUBLEARRAY
INTARRAY
DOUBLEAVERAGE

84. public class Exercise9
{
public static void main(String[] args)
{
int [] INTARRAY=new int [10];
int i;
for(i = 1;i<5;i++)
{
INTARRAY[i] = i * 2;
}
for(i = 1;i<5;i++)
{
System.out.println(INTARRAY[i]);
}
}
}
public class Lesson9
{
public static void main(String[] args)
{
int [] INTARRAY=new int [30];
int i;
double DOUBLEAVERAGE = 0.0;
double [] DOUBLEARRAY=new double [30];
for(i = 0;i<30;i++)
{
INTARRAY[i] = (i + 1) * 3;
DOUBLEAVERAGE = DOUBLEAVERAGE + INTARRAY[i];
}
DOUBLEAVERAGE/=30;
for(i = 0;i<30;i++)
{
DOUBLEARRAY[i] = INTARRAY[i] - DOUBLEAVERAGE;
}
System.out.println("MULTIPLE DIFFERENCE");
for(i = 0;i<30;i++)
{
System.out.println(INTARRAY[i]+"
"+DOUBLEARRAY[i]);
}
}
}

85. public class Array1
{
public Array1() { }
public static void main(String[] args){
String [] MySubjects = {"Math", "Science",
"English"};
String [] MyTeachers = {"Teacher1", "Teacher2",
"Teacher3"};
System.out.print("Here are my subjects: ");
System.out.print("My favorite subject is:
"+MySubjects[1]);
System.out.print("My favorite teacher is:
"+MyTeachers[2]);
}
}

87. dataType[] arrayRefVar;
dataType[] arrayRefVar[]
arrayRefVar = new dataType[arraySize]
dataType[] arrayREfVar = new dataType[arraySize]
dataType[] arrayRefVar = {value 0, value 1, …, valuen];

90. •
•
•
•
•

92. import javax.swing.*;
import java.awt.*;
public class Lesson10
{
public static void main(String[] args)
{
JFrame f1 = new JFrame("Joy de Jesus");
JPanel p1 = new JPanel();
JPanel p2 = new JPanel();
JPanel p3 = new JPanel();
JPanel p4 = new JPanel();
p1.setLayout(new GridLayout(2,2));
p2.setLayout(new GridLayout(2,2));
p3.setLayout(new GridLayout(2,2));
p4.setLayout(new GridLayout(2,2));
JButton b1 = new JButton("1");
p1.add(new JButton(" "));
p1.add(new JButton(" "));
p1.add(new JButton(" "));

93. p1.add(new JButton(" "));
p2.add(new JButton(" "));
p2.add(new JButton(" "));
p2.add(new JButton(" "));
p2.add(p1);
p3.add(new JButton(" "));
p3.add(new JButton(" "));
p3.add(new JButton(" "));
p3.add(p2);
p4.add(new JButton(" "));
p4.add(new JButton(" "));
p4.add(new JButton(" "));
p4.add(p3);
f1.setContentPane(p4);
f1.pack();
f1.show();
}
}
byte[] bytes = <any code generating byte array>
String content = new String(bytes);
readAllBytes() Files
byte[] bytes = Files.readAllBytes(<Path object>);

94. Path path = file.toPath();
File file = new File(uri);
String uri = resource.getFile();
ClassLoader
URL resource = classLoader.getResource(<string path and
file>);
ClasssLoader
getSystemClassLoader()
ClassLoader classLoader = ClassLoader.getSystemClassLoader();

96. package app.book.vc;
import app.book.model.Book;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import app.book.service.*;
public class GuiBook implements ActionListener {
private Book book;
private JPanel labelPanel = new JPanel();
private JPanel contentPanel = new JPanel();
private JPanel buttonPanel = new JPanel();
private static final String PREVIOUS_PAGE_BUTTON_LABEL = "Previous Page";
private static final String NEXT_PAGE_BUTTON_LABEL = "Next Page";
private JLabel labelPage = new JLabel();
private JTextArea labelContent = new JTextArea();
// private JScrollPane scrollPaneContent = new JScrollPane();
private JButton btnPrevPage = new JButton(PREVIOUS_PAGE_BUTTON_LABEL);
private JButton btnNextPage = new JButton(NEXT_PAGE_BUTTON_LABEL);
private BookService bookService;
package app.book.vc;
public class BookController {
public static void main(String args[]){
new GuiBook();
}
}

97. public GuiBook() {
String[] authors = {"Mrs. Goose"};
book = new Book("Title", 4, authors);
labelPage.setText(String.valueOf(book.getCurrentPage()));
labelPanel.add(labelPage);
// contentPanel.add(scrollPaneContent);
contentPanel.setBackground(Color.white);
contentPanel.setSize(360, 500);
contentPanel.add(labelContent);
btnPrevPage.addActionListener(this);
btnNextPage.addActionListener(this);
buttonPanel.add(btnPrevPage);
buttonPanel.add(btnNextPage);
buttonPanel.setSize(360,60);
JFrame jFrame = new JFrame("");
jFrame.add(labelPanel, BorderLayout.NORTH);
jFrame.add(contentPanel, BorderLayout.CENTER);
jFrame.add(buttonPanel, BorderLayout.SOUTH);
jFrame.setSize(360,560);
jFrame.show();
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.setResizable(false);
bookService = new BookServiceImpl();
labelContent.setText(bookService.turnPage(book.getCurrentPage()));
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals(NEXT_PAGE_BUTTON_LABEL)) {
book.turnPageForward();
}
if (e.getActionCommand().equals(PREVIOUS_PAGE_BUTTON_LABEL)) {
book.turnPageBackward();
}
labelPage.setText(String.valueOf(book.getCurrentPage()));
labelContent.setText(bookService.turnPage(book.getCurrentPage()));
}
}

98. package app.book.model;
public class Book extends ReadingMaterial {
private String[] authors;
public Book(String title, int totalPage, String authors[]) {
super(title, totalPage);
this.authors = authors;
}
public String[] getAuthors() {
return authors;
}
//override setCurrentPage, allow changing of page when selected page is
within bounds
public void setCurrentPage(int selectedPage) {
if (selectedPage > 0 && selectedPage <= getTotalPage()) {
super.setCurrentPage(selectedPage);
} else {
System.out.println("Invalid page " + selectedPage + ".");
}
}
}
package app.book.model;
public class ReadingMaterial {
private String title;
private int totalPage;
private int currentPage = 1;
public String getTitle() {
return title;
}
public int getTotalPage() {
return totalPage;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int turnPageForward(){
if (this.currentPage < this.totalPage) {
this.setCurrentPage(this.currentPage + 1);
}
return this.currentPage;
}

99. public int turnPageBackward() {
if (getCurrentPage() > 1) {
this.setCurrentPage(getCurrentPage() - 1);
}
return this.currentPage;
}
public int turnPageForward(int skipCount){
if (this.currentPage < this.totalPage) {
if (this.currentPage + skipCount > this.totalPage) {
this.setCurrentPage(this.totalPage);
}if (this.currentPage + skipCount < 1) {
this.setCurrentPage(1);
}
else {
this.setCurrentPage(this.currentPage + skipCount);
}
}
return this.currentPage;
}
public ReadingMaterial(String title, int totalPage) {
this.title = title;
this.totalPage = totalPage;
}
}
package app.book.service;
public interface BookService {
String turnPage(int page);
}

100. package app.book.service;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
public class BookServiceImpl implements BookService {
@Override
public String turnPage(int page) {
String content = "";
ClassLoader classLoader = ClassLoader.getSystemClassLoader();
URL resource = classLoader.getResource("txt/" + page);
String uri = resource.getFile();
File file = new File(uri);
Path path = file.toPath();
try {
byte[] bytes = Files.readAllBytes(path);
content = new String(bytes);
} catch (IOException e) {
e.printStackTrace();
}
return content;
}
}

101. 1 1
1
2 2
2
3 3
3
4 4
4 4
pack() show()

103. o
o
o
o
o
o
o