文档介绍：Alert 显示一个包含消息的对话框
AlertType
rithmeticException
ArrayIndexOutOfBoundsException
ArrayStoreException
Boolean
Byte
ByteArrayInputStream
ByteArrayOutputStream
Calendar 日历;
Canvas 画布
Certificate
CertificateException
Character
Choice
ChoiceGroup 单选框与复选框
Class
ClassCastException
ClassNotFoundException
CommConnection
Command 命令;
CommandListener
Connection
ConnectionNotFoundException
Connector
ContentConnection
Control
Controllable
CustomItem
DataInput
DataInputStream
DataOutput
DataOutputStream
Datagram
DatagramConnection
Date
DateField 接收日期的输入
Display
Displayable
Double
EOFException
EmptyStackException
Enumeration
Error
Exception
Float
Font
Form 容器类:能显示从Item派生的类
GameCanvas
Gauge 显示图形化的进度条
Graphics 虚拟画笔
Hashtable Hash表二维集合;
HttpConnection
HttpsConnection
IOException
essException
IllegalArgumentException
IllegalMonitorStateException
IllegalStateException
IllegalThreadStateException
Image 创建图片文件
ImageItem 显示存储在文件中的图像
IndexOutOfBoundsException
InputConnection
InputStream
InputStreamReader
InstantiationException
Integer
InterruptedException
InterruptedIOException
InvalidRecordIDException
Item Form的派生类;
mandListener
ItemStateListener
Layer 图层父类
LayerManager 图层管理
List 显示一个条目如菜单
Long
MIDlet
MIDletStateChangeException
Manager
Math
MediaException
NegativeArraySizeException
NoClassDefFoundError
NoSuchElementException
NullPointerException
NumberFormatException
Object
OutOfMemoryError
OutputConnection
OutputStream
OutputStreamWriter
Player
PlayerListener
PrintStream
PushRegistry
Random
Reader
parator
RecordEnumeration
RecordFilter
RecordListener
RecordStore
RecordStoreException
RecordStoreFullException
RecordStoreNotFoundException
RecordStoreNotOpenException
Runnable
Runtime
RuntimeException
Screen
SecureConnection
SecurityException
SecurityInfo
ServerSocketConnection
Short