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