Quiz Topics
6170, Fall 2000

Java Basics

Basic heap structure

• Variables, objects, fields
• Primitive types
• Null references

Sharing issues

• Aliasing & mutability
• Kinds of equality
• Parameter-passing mechanism

Subclassing

• The Object class: hashCode and equals
• Inheritance, overriding

Exceptions

• Checked and unchecked
• Standard exceptions
• When to use exceptions
• Exceptions vs. special values
• Run-time assertions

Namespace

• Package structure
• Access control
• Imports, overloading
• Standard library structure

Object Models

Basic elements

• Sets and relations
• Classification of sets
• Disjointness & exhaustiveness
• Multiplicity and mutability

Code interpretation

• Sets as classes and interfaces
• Relations as fields
• Sharing of objects
• Specification fields & eliding representations

Problem interpretation

• Avoiding implementation bias
• Dynamic classifications

Module Dependencies

Basic notions

• Difference between MDD and OM
• Weak and strong dependences
• Extends/implements

Common idioms

• Decoupling with interfaces
• Representation independence
• Polymorphic containers: dependence on Object

Abstract Data Types

Representation independence

Classification of operations

Mutable vs. immutable types

Abstraction functions

• Motivation: role in correctness argument
• General properties of all abstraction functions
• Common idioms
• Specification fields

Rep invariants

• Common idioms
• Structural induction
• As runtime assertions

Choice of representation

• Performance issues
• Code complexity issues

Benevolent side effects

Specifications of methods

• Preconditions
• Postconditions
• Modifies clauses
• Declarative specification

Representation exposure

• What it is
• Why problematic
• How to avoid

Equality notions

• Whether mutability is observable
• Abstract and concrete objects
• Abstract values and abstract objects
• Java approach, Liskov approach

Design Patterns

General

• When (not) to use

Creational

• Factory method
• Factory object
• Prototype

Sharing

• Interning
• Flyweight
• Singleton

Structural

• Wrappers: adapter, decorator, proxy
• Composite

Behavioural

• Observer, blackboard,mediator
• Traversal: visitor, interpreter

Testing

Kinds of testing

• black box, glass box

Alternatives to testing

Criteria

• coverage
• boundary cases
• duplication

Subtyping

Rationale

• Substitution principle

Subclassing vs. subtyping

Contravariance and covariance

• Strengthening/weakening, post/pre

Java issues

• Java interfaces
• What Java enforces