Diffrence between Service and Intentservice in Android?

Below are some key differences between Service and IntentService.

When to use?

The Service can be used in tasks with no UI, but shouldn't be too long. If you need to perform long tasks, you must use threads within Service.

The IntentService can be used in long tasks usually with no communication to Main Thread. If communication is required, can use Main Thread handler or broadcast intents. Another case of use is when callbacks are needed (Intent triggered tasks).

How to trigger?

The Service is triggered by calling method startService().

The IntentService is triggered using an Intent, it spawns a new worker thread and the method onHandleIntent() is called on this thread.

Triggered From

The Service and IntentService may be triggered from any thread, activity or other application component.
Runs On

The Service runs in background but it runs on the Main Thread of the application.

The IntentService runs on a separate worker thread.

Limitations / Drawbacks

The Service may block the Main Thread of the application.

The IntentService cannot run tasks in parallel. Hence all the consecutive intents will go into the message queue for the worker thread and will execute sequentially.

When to stop?

If you implement a Service, it is your responsibility to stop the service when its work is done, by calling stopSelf() or stopService(). (If you only want to provide binding, you don't need to implement this method).

The IntentService stops the service after all start requests have been handled, so you never have to call stopSelf().

What is sleep mode in Android?

Sleep mode means CPU is sleeping and it doesn't accept any commands from android device except Radio interface layer and alarm.

What is the order of buttons on dialogbox in android?

Positive, Neutral, Negative

Can you call one constructor from another, If a class has multiple constructor?

Yes, Use this() syntax.

Write two advantag and disadvantage of Agile and water fall model?

Waterfall model advantages:

• This model is simple and easy to understand and use.
• It is easy to manage due to the rigidity of the model – each phase has specific deliverables and a review process.
• In this model phases are processed and completed one at a time. Phases do not overlap.
• Waterfall model works well for smaller projects where requirements are very well understood.

Waterfall model disadvantages:

• Once an application is in the test stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.
• No working software is produced until late during the life cycle.
• High amounts of risk and uncertainty.
• Not a good model for complex and object-oriented projects.
• Poor model for long and ongoing projects.
• Not suitable for the projects where requirements are at a moderate to high risk of changing.

Advantages of Agile methodologies:

• Customer satisfaction by rapid, continuous delivery of useful software.
• People and interactions are emphasized rather than process and tools. Customers, developers and testers constantly interact with each other.
• Working software is delivered frequently (weeks rather than months).
• Face-to-face conversation is the best form of communication.
• Close, daily cooperation between business people and developers.
• Continuous attention to technical excellence and good design.
• Regular adaptation to changing circumstances.
• Even late changes in requirements are welcomed

 Disadvantages of Agile methogologies:

• In case of some software deliverables, especially the large ones, it is difficult to assess the effort required at the beginning of the software development life cycle.
• There is lack of emphasis on necessary designing and documentation.
• The project can easily get taken off track if the customer representative is not clear what final outcome that they want.
• Only senior programmers are capable of taking the kind of decisions required during the development process. Hence it has no place for newbie programmers, unless combined with experienced resources.

Is it okay to change the name of an application after its deployment?

How can two Android applications share same Linux user ID and share same VM?