Java Topics

You may have one 8.5 x 11 inch page of notes marked any way you want (as long as you can read them unaided or with your normal prescription eyewear).

Object Oriented Programming

• What basic 3 things make OOP powerful and popular?

• What is a class? What is an object? How are the two related?

• Are primitive types objects in Java?

• What is the difference between == and .equals( ) ?

• What does it mean to overload a method or constructor?

• How do you override a method? How do you get to the superclass’ implementation?

• What is polymorphism? Why do we want to represent objects as simpler types than they actually are?

• What is an abstract class? What is an interface? What is the difference between the two? When would you use one versus the other?

• What is message passing? How does message passing protect an object and provide encapsulation?

• Where can you see variables marked

  • public

  • protected

  • default (no modifier used)

  • private

• How is the final keyword used? What does it mean for a class to be final? A method? A variable?

Inner Classes & Listeners

• What is a nested class? What is the difference between a static and a non-static nested class?

• How do you create an instance of a static nested class?

• How do you create an instance of a non-static nested class from within the enclosing class? From outside the enclosing class?

• What scope may an inner (or non-static nested) class have?

• How do you declare an anonymous class? May anonymous classes extend other classes or implement interfaces?

• What makes up the state data of inner classes declared at different scopes?

• Describe the “Listener” pattern of events used by Java?

• Why are inner classes often used to implement listeners? How is this an improvement over directly implementing the listener interface in top-level class?

• How do adapter classes simplify implementing listener interfaces?

Strings, Text, and Regular Expressions

• Why is it significant that Strings are immutable?

• How can String literals be used in source code?

• What is the String pool? What are two ways it is accessed or used?

• How can Strings be compared?

• What are some common operations on Strings?

• What is the difference between a String, a StringBuilder, and a StringBuffer?

• What is the scanner class used for?

• Describe how printf is used to provide formatted output. Recognize and be able use formatting parameters (limited to: %b, %c, %d, %f, %s) in format strings HoHohhhsdfsflksafjklHHow.

• Be familiar with the following regular expression character classes: .(dot) \s \S \w \W \d \D

• Be familiar with the following regular expression multiplicity operators: * + ?

• How do you define your own character classes? How do you use the ^ and && symbols when doing this?

• How is the alternation (|) operator used in regular expressions?

• How are regular expression groups defined and used? How does the non-capture group symbol (?:) affect retrieving captured data? How can you get at captured data?

• How are the Pattern and Matcher classes used to parse text? How can the Scanner class use regular expressions to read text?

JavaBeans

• What are they? How are they used?

• What must a bean have/do?

• Bean Properties (Bound and Unbound)

• Bean Events (including custom events)

Generics

• What is a type parameter?

• What does “type erasure” mean?

• What is a “raw” type?

• What are bounded type paramters?

• Polymorphism and generics

• Using wildcards, bounding wildcards, what kinds of operations are safe.

• Generic methods

Collections

• What is provided by the Java Collections Framework?

• Why are there both interfaces and implemented classes in the framework?

• What are they basic interface types in the framework? What are their contracts?

• Which classes in the framework are inherently thread safe?

• Iterable, Iterator, Comparable, Comparator

• What does the Collections class provide for you?

• Deep vs. Shallow copies

Swing

• What are the main differences between Swing and AWT?

• How are Swing Components laid out? What properties are used?

• What is a Layout Manager? What are the most common ones? How do they work?

• What is a ContentPane?

• How do common GUI events work?

  • Button Clicks

  • List Box Selection

  • Dialog Boxes

  • Choosing Files

Threads

• What is a process? What is a thread?

• How do you start a thread?

• Thread class vs. Runnable interface

• What are the 4 basic thread states?

• How does the thread manager work? What behavior is guaranteed?

• Threading methods

  • stop, suspend, resume, destroy

  • wait, notify, notifyAll

  • sleep, interrupt

• What are Daemon threads?

• How are threads controlled?