1. JAVA

2. Stuff about Java
• Programming language
• Runs on a “virtual machine” (JVM)
• Platform Independent (Can run on any
machine)
• Object Oriented Language
• Automatic Garbage Collection

3. DATA TYPES
• boolean: Truth value (true or
false).
• int: Integer (0, 1, -47).
• double: Real number (3.14,
1.0, -2.1).
• String: Text (“hello world”).

4. Declaring and Assigning
Variables
Form: Type name;
Examples:
• String me = “Kenny”;
• int x = 4;
• double y;

5. Operators
• Assignment: =
• Addition: +
• Subtraction: • Multiplication: *
• Division: /
Form: varName Op varName;
Order of Operation follow
standard rules

6. Methods
Form: modifiers return_type name(arguments){
statements
}
To Call:
name(arguments);
Examples: public static void myMethod(int arg){
int x = 4
}
public static void myMethod(int arg){
int x = 4
return x;
}

7. if and “else if” Statement
Form: If (condition){
}
Example: if(x < 4){
System.out.println(“x is less than 4”);
} else if(x > 4){
System.out.println(“x is greater than 4”);
} else{
System.out.println(“x must be equal to 4”);
}

8. COMPARISON OPERATORS
•
•
•
•
•
•
x > y: x is greater than y
x < y: x is less than y
x >= y: x is greater than or equal to x
x <= y: x is less than or equal to y
x == y: x equals y
( equality: ==, assignment: = )

9. Boolean Operators
• &&: logical AND
return true if true
• ||: logical OR
returns false if false
Example: if ( x > 6 && x < 9)

10. Loops
Loops
Information
while
Runs while condition is true
While(x < 4){
dostuff();
}
do … while
Runs for the first time without checking then runs
while condition is true
do{
Stuff();
}while(x < 4);
For
Runs with optional counter while condition is true
For(int I = 0; I < 4, x < 4; i++){
doStuff();
}

11. Arrays
•
•
•
•
An indexed list of values
Any data type
All elements must have the same type
Form: type[] name = { val1, val2, val3 }; OR
type[ ] name = new type[noOfValues];
Int [] a = { 3, 5, 6, 8, 11, 12, 15, 17, 19, 20 }
Value:
Index:
a[0] a[1]
a[2] a[3] a[4] a[5] a[6] a[7] a[8] a[9]
System.out.println(a[5]);
output: 12

12. Classes
To model real world problems
// little baby 1
String name1;double weight1;
// little baby2
String name2;double weight2;
// little baby 3
String name3;double weight3;
For 500 babies inefficient!!!

13. • Using Classes
 Create a class Baby
 Then an array of baby or
babies
public class Baby {
String name;
boolean isMale;
double weight;
double decibels;
}
Baby[] babies = new Baby[500];
•
Classes can also contain methods
public class Baby {
…
Eat()
{
weight += 1;
}
}

14. Inheritance
• When a class inherits another class it has the
characteristics of that class plus its own.
• Classes inherit from one class
• Example: A class Car can inherit from another
class vehicle.
• Form: modifier class className extends baseClass {
}

15. Interfaces
• Interfaces are like classes that cannot have
object instances assigned.
• They can only be implemented by classes.
• Classes can implement many interfaces.
• Example:
interface move {
void accelerate();
void speed();
}

16. QUESTIONS?