Test 1 Review: Topic Checklist

Java Topics

Building Basic Java Programs

• A Java source file must end with the extension .java and should have the exact same name as the public class name.
• To compile a class in a Java source code file (say Yadda.java) type:
  javac Yadda.java
• Each class (there may be more than one) in a source code file, is compiled into a .class file.
• To execute a java application (say named Yadda.class) type
  java Yadda
• The main method has the following signature
  public static void main(String[] args)

Basic C++/Java differences

• Java identifier names also can use dollar sign ($)
• Built-in types: (bool vs. boolean, byte, sizes of types specified exactly for Java, etc)
• Java methods (functions) are all members of a class
• final vs. const
• test expresions in if-statements and loops must be Boolean expressions only, in Java
• modifiers (public, private, etc) go on the function headers in java
• Other basic syntax differences, as laid out in chart

Classes and Objects

• Objects and classes and the relationship between them
• Constructors: what they are and how to build them
• The modifiers public and private
• The static modifier, and the difference between static variables and methods vs. instance variables and methods, as well as which variables can be accessed from which methods
• Understand how to declare an object reference variable and then create the object with new, along with how to invoke the chosen constructor
• Understand how objects are passed in and out of methods
• Class scope vs. local scope (like in a method)
• The keyword this

Arrays

• Understand arrays, this includes multi-dimensional arrays
• Know how to declare an array variable, and then create the array with the new operator
  int[] array1 = new int[size];

• Know that the length of an array (say named array) can be found by using array.length
• Know that the reference (name) of an array can point to any array of that type
  (two array references can point to the same array)
• Understand all the ways to declare an array variable. All the following are the same and are legal
  (the first is the preferred way):

  int[][][] thingy;
  int[][] thingy[];
  int[] thingy[][];
  int thingy[][][];
  

• Understand how to declare, create, and initialize an array all at once
  int[] bubba = {2, 5, -56};
• Know how to pass arrays in and out of methods, and understand the effects (i.e. does the method have access to change original argument?)
• Arrays of objects (array of reference variables, each can attach to an object)

Some practice array algorithms to try (coding practice)

• Compute and print the sum (product, average) of the elements of a numerical array.
• A method that returns the maximum element of an array
• A method that prints all array elements that are between two given values (parameters)
• A method that counts up all the even numbers in an array
• A method that returns an array that contains all odd elements from an original array (incoming parameter)

Strings

• Understand the difference between a String (immutable) and a StringBuffer (mutable)
• Understand the common String methods: length(), concat(), equals(), compareTo(), charAt(), substring(), trim(), toLowerCase(), toUpperCase(), replace()
• Understand the common StringBuffer methods: construction from a String, append(), insert(), delete(), length(), charAt(), substring()

Inheritance and Polymorphism

• Superclasses and subclasses, and deriving a class with the keyword extends
• The use of super to invoke parent constructors and methods
• Understand overriding methods in derived classes
• Every class is derived in some way from class Object. Understand the toString() method, inherited from Object by every class:
• Understand the modifiers protected and final, and what they do when applied to class data and methods
• Abstract classes and their relationship with abstract methods
• Understand polymorphism and dynamic binding
  • How base class variables can be attached to derived class objects
  • How base class methods can be overridden in derived classes
  • How dynamic binding allows method calls (through base class variables) to still invoke child versions of overridden methods
  • When casting is necessary between parent and child, and when it is not
• Understand interfaces, how to declare one and how to extend one
• Know how a class declares that it will implement an interface
• Understand relationship of data and methods with interfaces
• Understand the basic interfaces discussed in examples (Comparable and Clonable)

Object-Oriented Design And Analysis Topics

Basic concepts

• Know the basic steps of software development (problem definition, analysis, design, implementation, testing)
• Be able to name other activities involved in software engineering
• Understand what a model is, and be able to define the terms view and notation as they pertain to modeling
• Understand the difference between application domain and solution domain
• Know the primary parts of a system's model (functional model, object model, dynamic model), and what the difference is between them
• UML diagram types -- know what the difference is between the basic types of diagrams we have listed
  • While you've only seen the specifics of class/object diagrams and use case diagrams, you should be able to name some others, and give a basic sentence describing what they are for

UML Class Diagrams

• Understand the basic notations of representing a class in a UML diagram
  • class is a Rectangle, with 3 possible compartments
  • compartments are for name, attributes, behaviors
  • Understand how to do the full signatures
• Understand how to represent the basic types of relationships between classes, including:
  • basic association (can be directed, can be labelled, etc)
  • Aggregation and the stronger form, composition
  • generalization (and the similar form for interfaces)
• Understand how to represent multiplicities, role names, abstract classes, and other diagram elements discussed in class
• Given an example design, be able to draw a class diagram representing that design

Use Cases and UML Use Case Diagrams

• Understand what a use case is, and how to describe one
• Understand what an actor is, and how it relates to use cases
• Understand what a scenario is, and how it relates to use cases
• Know the basic specification of a use case used by our textbook
  • Name
  • participating actors
  • Entry Conditions
  • flow of events
  • Exit conditions
  • Quality requirements
• Understand the UML use case diagram elements, including how to represent use cases, actors, and communication between them
• Understand the three primary relationships (or associations) between use cases, as well as how to represent them on a UML use case diagram:
  • extend
  • include
  • generalization

Requirements Specification

• Understand what is meant by requirements elicitation
• Know the difference between different types of requirements:
  • functional requirements
  • non-functional requirements (specifically, quality requirements)
  • constraints (pseudo-requirements)
• When it comes to testing and validating requirements, understand what it means to check that the requirements are:
  • complete
  • consistent
  • unambiguous
  • correct
  • realistic
  • verifiable
  • traceable
• Be able to discuss some general techniques for coming up with requirements
  • Examples: observation of current work processes, interviews, starting with specific scenarios and generalizing to use cases, etc