用一个简单的例子来看MIDlet的生命周期原文

public class HelloWorld extends MIDlet ......{

    public HelloWorld() ......{ 
        System.out.println("这个是程序的构造函数，程序运行的时候首先调用这个");
    }

    protected void destroyApp(boolean unconditional)
            throws MIDletStateChangeException ......{
        System.out.println("这个是程序的destroyed事件，当您按下退出时调用");
    }

    protected void pauseApp() ......{
        System.out.println("这个是程序的pause事件，当您按下暂停的时调用");

    }

    protected void startApp() throws MIDletStateChangeException ......{
        System.out.println("这个是程序的active事件，程序启动时候调用");

    }

}

public static void main(String args[]) ...{
        CommandState state = new CommandState();

    /**//*
     * pass resource strings down to the native system menu and
     * popup choice group methods...
     */
    initSystemLabels();

        /**//*
         * We will try to handle any printing at this level, because
         * displaying JAM command line errors is device specific.
         */
        try ...{
            initializeInternalSecurity();

        /**//* Start a inbound connection watcher thread. */
        new Thread(new PushRegistryImpl()).start();

            restoreCommandState(state);

            // handle any development machine only functions at this level
            switch (state.nextCommand) ...{
            case CommandProcessor.RUN_CLASS:
                runLocalClass(state);
                state.nextCommand = CommandProcessor.EXIT;
                break;

            case CommandProcessor.MANAGE:
                manage(state);
                break;

            case CommandProcessor.LIST:
            case CommandProcessor.STORAGE_NAMES:
                list(state);
                state.nextCommand = CommandProcessor.EXIT;
                break;

            case CommandProcessor.REMOVE:
                if (DEV_STORAGE_NAME.equals(state.suiteStorageName)) ...{
                    removeDevStorage(state);
                    state.nextCommand = CommandProcessor.EXIT;
                    break;
                }

                // fall through
            default:
                CommandProcessor.perform(state);
                if (state.status == CommandProcessor.MIDLET_SUITE_NOT_FOUND) ...{
                    System.out.println("The MIDlet suite was not found.");
                } else if (state.initialCommand == CommandProcessor.INSTALL &&
                        state.status == CommandProcessor.OK) ...{
                    System.out.println("Storage name: " +
                                       state.suiteStorageName);
                }
            }
        } catch (InvalidJadException ije) ...{
            System.out.println("** Error installing suite (" +
                               ije.getReason() + "): " + 
                               messageForInvalidJadException(ije));
        } catch (IOException ioe) ...{
            System.out.println("** Error installing suite: " +
                               ioe.getMessage());
        } catch (ClassNotFoundException ex) ...{
            if (state.initialCommand == CommandProcessor.MANAGE) ...{

              state.runExceptionMessage =
                    Resource.getString("The application cannot be launched. " +
                    "One of the application classes appears to be missing. " +
                    "This could be due to a mis-named class. Contact the " +
                    "application provider to resolve the issue.");
            } else ...{
                System.out.println("MIDlet class(s) not found: " + 
                                   ex.getMessage());
            }
        } catch (InstantiationException ex) ...{
            if (state.initialCommand == CommandProcessor.MANAGE) ...{
               state.runExceptionMessage = Resource.getString(
                   "The application cannot be launched. The application " +
                   "may have done an illegal operation. Contact the " +
                   "application provider to resolve the issue.") + " " +
                   ex.getMessage();
            } else ...{
                System.out.println(
                    "MIDlet instance(s) could not be created: " + 
                                 ex.getMessage());
            }
        } catch (IllegalAccessException ex) ...{
            if (state.initialCommand == CommandProcessor.MANAGE) ...{
                state.runExceptionMessage = Resource.getString(
                   "The application cannot be launched. The application " +
                   "may have done an illegal operation. Contact the " +
                   "application provider to resolve the issue.") + " " +
                   ex.getMessage();
            } else ...{
                System.out.println(
                    "MIDlet class(s) could not be accessed: " + 
                    ex.getMessage());
            }
        } catch (OutOfMemoryError ex) ...{
            if (state.initialCommand == CommandProcessor.MANAGE) ...{
                state.runExceptionMessage = Resource.getString(
                    "The application has unexpectedly quit because it ran " +
                    "out of memory.");
            } else ...{
                System.out.println("The MIDlet has run out of memory");
   &nb