Final Exam Flashcards
Hard Drive
Stores data
RAM
Temporarily stores data
Which storage does the processor use?
RAM
What are programming languages listed high to low level?
Pseudo > high > assembly > machine
Name high level object oriented programming languages
C#, C++, Java
What is java assembly language?
Java bytecode for JVM
What is machine code?
Binary, executable
What does compiler do?
Converts code into executable form
What does interpretor do?
Translates while running program
How is java compiled?
By Javac to bytecode
What is bytecode?
A special portable executable for Java compiled by Javac
What are the phases of programming?
Define/analyze, design, write code, test code, document, maintain/upgrade
What are the three data types?
Primitive, collections, and objects
What is one byte?
8 bits
What are boolean, byte, char, short, and float?
Primitive variables
What must at least one class in a project have?
A main method
What is structured processing?
Inputing data, processing, and producing output
Sequence, decisions, loops
What is procedural processing?
Passing data, processing, and returning values
What is object oriented processing?
Defining data attributes and methods that operate on them, creating powerful new data types
What are the different types of identifiers?
Classes, methods, variable names
Identifiers can contain:
Letters, digits, and $
What are " , \ , \n , \t ?
Escape sequences
When is final used?
For constants whose values do not change
Postfix - int y = x++ results in:
Y is a number, then x is incremented
Prefix - int y = ++x results in:
x is incremented, then y is set to incremented number
What is Java API?
Set of pre-existing software; some of which needs to be imported
Are static methods instantiated or called?
Does not need to be instantiated, just called
If a static method is in a different class how do you call it?
With “Classname.methodName(params)”
How do you call a method that belongs to an object?
objectVariable.methodName(params)
Where does character index start?
0
Use _____ operator to combine strings
+
Scanner methods are:
next() nextInt() nextDouble() next().charAt(0) nextLine() (nextLine does not skip spaces, tabs and newlines to get next item)
String1 == string2 compares what?
Reference variables and location in memory
What are some character methods?
isLetter()
isDigit()
toUpperCase()
toLowercase()
What are some object reference variables?
Arrays, API library, user-defined classes
What is a reference variable?
Contain references to objects in memory where actual data is stored.
What do objects do with primitives passed to them?
Make copies
What is the switch format?
switch (variable) {
case c1: statement;
break;
case c2: statement;
break;
}Benefit of switch format?
Can have multiple cases on one line
Order of operations
() - negation, ! not, casting, ++, -- *, /, % \+, -, concat , <=, >= ==, != && || =, *=, %=, etc
Two types of loop designs
Counter controlled - certain number of times
(for loop)
and
Sentinel controlled - until event/value occurs
(while and do/while loop)
Checks condition after running once
For loop
Checks condition before running
While loop
Does the do statement, then checks condition, then returns to complete those conditions if while condition is met
Do/while loop
What happens when “return” is encountered?
Method immediately ends
Static methods
Can be called without being instantiated
When passed to methods, primitives:
Are copied
When passed to methods, objects:
Addresses are passed so they are directly acted on
Scope
Where variables can be used
Variables with the same name can be declared in separate blocks/methods UNLESS:
Nested
Math.
pow(number to square, power) sqrt(#) cell(#) floor(#) round(#) PI E
Lets you create an object of primitive type
Wrapper class
What does stringBuffer do?
Lets you change characters
toString()
length(), etc
When can you call a static method from another class?
When both classes are in the same package
How to call for each loop
for (TypeOfData anyWordYouWant: nameOfArray) {
actions
}
When arrays are created, primitives are set to ____, and reference objects are set to ____
0 and null
4 types of access specifiers
Public - accessible by anything
Protected - same folder only
Private - only within the same class
Default - package private
What do classes do?
Defining new data types
How do you instantiate a class?
Create variables of the class type and calling a constructor
What does a class contain?
Data and methods
Which data type do classes contain?
Static and instance
What is a static data type?
It does not need to be instantiated and only one copy is shared by all objects of the class
Static methods do not use instance members to do its job. T or F?
True
Static methods are called with ______
Class name
What is instance data?
Each object has its own copies and values
How are instance methods called?
With a class object and may operate directly on any data members
How to override a static method
You cannot. The point of a static method is that it is the same method throughout all objects
How can you compare object addresses?
==
How can you compare objects?
.equals()
Immutable
Cannot be changed after being created
Ex. Integer, Double, and String
Object array syntax?
FirstClass rays[] = new FirstClass[10]
Rays[0] = new FirstClass(‘a’, 10)
What is overloading?
Same method name with different parameters
Inheritance
Creating a subclass by extending a superclass
Overriding
Redefining a super method in the subclass
Relationships
Uses - class uses method/data of another class
Has - class has instance of another class/method
Is - is a subclass of another class
Super keyword
Calls super class
How can subclasses directly access and use private members?
Use super.get or super.set methods
You can extend from how many classes?
One
What is shared with extended class?
All methods
Upcasting
Cast subclass to superclass type
Shares methods and data of superclass
Upcasting is implicit. Tor F?
True
Downcasting is implicit. T or F?
False. Explicit
Static methods can not access instance data. T or F?
True
Instance methods can not access static data. T or F?
False. They can access static data
Recursion
Method repeatedly calls itself
Iteration
Method uses loops without repeatedly calling itself
