Chapter 1: Introduction to Computers the Internet and Java

Nuggets

• Three different versions of Java
  • SE: Standard Edition
  • EE: Enterprise Edition (additional components for web and distributed programming)
  • ME: Micro Edition (subset of SE for resource-constrained devices)
• Java Programming Paradigms
  • Procedural
  • Object-Oriented
  • Generic
  • (Java 8) Functional Programming (easier to parallelize)

---

Chapter 2: Introduction to Java Applications: Input/Output and Operators

Nuggets

• Three types of comments
  • // end of line
  • /* */ multiple line
  • /** */ javadoc
• Naming
  • Class Name and Filename must match
  • Class Names should begin with an Upper Case and Capitalize the first letter of each word, camel case
• Strings cannot span multiple lines

Snippets

• public static void main(String[] args) {}  //program load point
• public static void main(String … args) {} //alternate program load point using elipses
• javac Welcome1.java  //Compiles the java class Welcome1
• java Welcome1 //run the Welcome1 program
• import java.util.Scanner; // keyboard
• Scanner kb = new Scanner(System.in); //kb object to get nextLine, nextInt, etc.
• String name = JOptionPane.showInputDialog(“What is your name?”); //Input dialog box, stores entered value into variable “name”
• JOptionPane.showMessageDialog(null, message); //Message Dialog box
• System.out.printf(“This is a string %s and this is an integer %d and this is 2 decimal float %.2f and this is new line %n”,strAString, intANumber, floatAFloat); //Formatted Output
• Some operators
  • == //equals — use with a number or to mean the same object reference, strings s.equals(aString)
  • != //not equals
  • <= //less than or equal to
  • >= //greater than or equal to
• import javax.swing.JOptionPane; //swing class JOptionPane

---

Chapter 3: Control Statements Part 1: Assignment, ++, and — operators

Nuggets

• TERM: Transfer of Control: the next statement is not always the one that executes
• 3 Control Structures
  • Sequence
  • Selection
    • Single-selection (if)
    • Double-selection (if…else)
    • Multiple-selection (switch)
  • Repetition/Iteration/Looping
    • while
    • do while
    • for
    • enhanced for
• Conditional Operator (?:)  — Java’s only ternary operator (conditional ? true : false)
• sentinel-controlled repitition — have some condition or user input to signal the end of the loop
• unary cast operator: (double) average = (double) (n1 + n2)/n3
• compound assignment operator:
  • c += 7; // c = c + 7
  • d -= 4; // d = d – 4
  • e *= 5; // e = e * 5
  • f /= 3; // f = f / 3
  • g %= 9; // g = g % 9
• preincrementing / predecrementing:   ++a ; –a;
• postincrementing  / postdecrementing: a++; a–;
• strongly typed languague (primitive data types)
• extends (a class is an enhanced version of a class)
• inherits (when a class extends another class it gets the other class’s methods and attributes)
• superclass / subclass: parent/child; base/derived

Snippets

• if {} else if {} else {}
• System.out.println(studentGrade >= 60 ? “Passed” : “Failed”);
• while () {}

---

Chapter 4:  Control Statements: Part 2: Logical Operators

Nuggets

• Essentials of Counter-controlled Repetition
  • Control variable (loop counter)
  • initial value of the control variable
  • increment (how the control variable is modified each time)
  • loop-continuation condition (determines if we continue to loop)
• break; // terminates the loop
• continue; // skip back to the controlling statement
• conditional and (&&), conditional or (||) xor (^)
  • && : both must be true in order to be true
  • ||: both must be false in order to be false
  • ^: true if only one is true
  • !: negation
• 3 forms of control
  • sequence
  • selection
  • repetition

Snippets

• for (int counter = 1; counter <= 10; counter++){}
• for (;;) {}
• while () {}
• do {} while ();
• switch () { case x: statement; break; default: statement; break;}

---

Chapter 5: Methods

Nuggets:

• Static Method or Class Method applies to the class and can be called directly: Math.pow
• Static Variables: Math.PI, Math.E
• String concatenation “Hello ” + “World”
• argument promotion, java will attempt to promote what you send to the correct variable type
• If a block contains a variable name used elsewhere the other name is hidden until the block terminates — this is called shadowing.  You can access the shadowed variable by using the ClassName.variableName;
• Method overloading: same method name, different variable types

Snippets

• Key Java API packages
  • java.awt.event
  • java.awt.geom  // 2D shapes
  • java.io
  • java.lang
  • java.net // networking
  • java.security
  • java.sql // SQL package
  • java.util
  • java.util.concurrent // parallel execution
  • javax.swing // GUI components
  • javax.swing.event // GUI events
  • javax.xml.ws // web services
  • javafx.packages // preferred GUI
  • java.time // Java 8 – Date/Time API
  • java.util.function & java.util.stream // Java 8
• SecureRandom randomNumbers = new SecureRandom();
• private enum Status { CONTINUE, WON, LOST };

Chapter 6:

---

Chapter 7: Introduction to Classes and Objects

TERM: Extensible Language: You can add classes/types

TERM: Instance Variable: attributes of a class

TERM: Application Class: Has a main method that calls the class

SNIPPET: public class Account

• public — access modifier
• class — keyword
• Account — class name, must be in a file named Account.class

TERM: Instance Methods: Nonstatic methods

CONVENTION: Class names use Camel Case where names begin with an upper case letter

CONVENTION: Method names use Camel Case where names begin with a lower case letter

TERM: Shadowed Instance variable: Variable declared at instance and local variable

TERM: Driver Class: calls another class

CONCEPT: Static can be called directly

public class A
{
double void f1;
double static f2;
}
A a = new A();
a.f1();
A.f2();

CONCEPT: Private allows information hiding / data hiding

CONCEPT: Local variables are not initialized by default

CONCEPT: Constructors can be private and cannot return a value

UML:

• + public
• – private
• <<constructor>>  guillemets

SNIPPETS

• total += grade; // accumulation
• return (double) total / grades.length; // note casting
• for (int grade : grades) //loop over grades array