7.1

int[][] triArray{

	{1},

	{1,2},

	{1,2,3},

};

7.2

array[2].length

8.1

Unified Modeling Language:UML

UML class diagram

Circle

_____________

radius:double

_____________

+Circle()

+Circle(newRadius:double)

getArea():double

circle1:Circle

_________

radius = 19

8.2

client

8.3

reference variable

ClassName objectRefVar;

null

NullPointerException

8.4

object member access operator:.

instance variable

instance method

static variable:class variable

static method

getter:accessor

setter:mutator

pass by value

calling object

8.5

java.util.Date

+Date()

+Date(elapseTime:long)

+toString():String

+getTime():long

+setTime(elapseTime: long)void

8.6

java.util.Random

+Random()

+Random(seed:long)

+nextInt():int

+nextInt(n:int):int

+nextLong():long

+nextDouble():double

+nextFloat():float

+nextBoolean():boolean

//Random random1 = new Random(3)

8.7

javax.swing.JFrame

Jframe frame1 = new JFrame();

frame1.setTitle("Window 1");

frame1.setSize(200,150);

frame1.setLocation(200,100);

frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame1.setVisible(true);

JButton jbtOK = new JButton("OK");

JLabel jlblName = new JLabel("Enter your name: ");

JTextField jtfName = new JTextField("Type in here");

JCheckBox jchkBold = new JCheckBox("B");

JRadioButton jrbRed = new JRadioButton("Red");

JComboBox jcboColor = new JComboBox(new String[]{"freshman","sophomore","junior","senior"});

JPanel panel = new JPanel();

panel.add(jbtOK);

8.8

Math.PI

8.9

package-private:package-access

private:类的成员

public:类

Keyword:

accessor method:getter method

action

attribute

behavior

class

client

constructor

data field

date-field encapsulation

default constructor

dot operator:object access operator

instance

instance method

instance variable

instantiation

mutator method:setter

null

no-arg constructor

object-oriented programming:OOP

Unified Modeling Language:UML

package-private:package-access

private

property

public

reference variable

reference type

state

static variable

static method