MidTerm Flashcards
Variable represented in
Unicode
Variable Name
must start with a character, and can include any unicode character
Two datatypes of Java
Primitive and Non-primitive
Primitive examples
byte, short, long, int, float, double, boolean and char
Non-primitive examples
String, Array, Classes
byte size
1 byte; -2^7 to 2^7 where 7 = 8 - 1
short size
2 byte; -2^15 to 2^15 where 15 = 2x8-1
int size
4 byte; -2^31 to 2^31 where 31 = 4x8-1
long size
8 byte; -2^(8x8-1) to 2^(8x8-1)
char size
2 byte
float
4 byte; 6 to 7 decimals
double
8 byte; 15 decimals
in Java, non-primitives are known as
reference types
Shortcut If then else
exp ? true : false
Strongly typed is
strict rule with data type conversion
Statically typed
safe and secure; it cannot ever be bound to an object of a different type
Dynamically typed
unpredictable behavior; can be assigned to objects of different type
Strings are
immutable
If you wish to have a string you can change the value of you should use
Stringbuffer
If i want to concat a string together how?
s=s.concat(“ appended”);
A ______ is a non-primitive data type in Java, while an _______ is an instance of a class
class object
Why a class is the blueprint or template for an object ?
the complete syntax for handling encapsulation, abstraction, polymorphism, and inheritance
before compilation file extension for class
.java
after compilation file extension for class
.class
during execution .class file is run
in the JVM
syntax for methods that return a value
public returnType methodName(parameters){
}
accessing attributes outside the class definition
.
myBestFriend._name = “Lara”;
Formal parameters
are declared in the method heading
+ UML Class Diagram
public
- UML Class Diagram
private
Instance Variables
class variables basically
what does a class variable hold?
a memory address
what does a primitive variable hold?
a value
Aliases
multiple class variables that have the same memory address. They point to the same object.
Do not use _______ operator with two class variables
==. Use someClass.equals(otherClass);
