Saturday, April 21, 2007

JAVA 認證心得 -- SCMAD (1)

JTWI (JSR 185)


  • In JTWI
  • The minimum application thread count is 10
  • text/ is the MIME type for JAD file.
  • Java Technology for Wireless Industry (JTWI) is a meta-specification. So JTWI does not define any API.
  • MIDIControl must be supported by a JTWI 1.0 compliant device to support MIDI playback. Note that this control need not be supported by a device that is only MIDP 2.0 compliant.
  • A JTWI 1.0 compliant device that supports MMAPI 1.1 specification must implement VolumeControl interface for the Player instances.
  • A JTWI 1.0 compliant device the value returned by the Canvas.getWidth() and Canvas.getHeight() method must be at least 125 pixels.
  • A JTWI 1.0 compliant device must implement a mechanism for selecting a phone number from the device phone book when the user is editing a TextBox or TextField and the constraint is TextField.PHONENUMBER.
  • To identify a JTWI-complicant device and the implemented version of this specification the value of the system property microedition.jtwi.version must be “1.0”
  • A JTWI 1.0 compliant implementation must allow a MIDlet suite to create a minimum of 5 simultaneously running Timers.
  • The minimum volatile memory requirement for the Java Virtual Machine according to the JTWI 1.0 specifications is 256KB
  • The MIDlet-Data-Size attribute refers to the RMS data size.MIDlet-Data-Size should be the minimum amount of space for RMS that the application can work with. According to the JTWI 1.0 specification, this should be 30KB.
  • The implementation of SocketConnection using TCP sockets will throw java.securityException when an untrustedMIDlet suite attempts to connect to ports 80 and 8080, and 443
  • The JTWI specification requirements only for the untrusted domain for GSM compliant devices.

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