"Can you do me a favor?" "Can you come here a second?" "HELP!"

It's an attempt to use emotional leverage to acquire assistance.

In the author's case they're appealing to prowess; "if you can help me with this then clearly you are an accomplished java person."

In my first two examples it's usually someone leveraging the nature of your relationship; "if you care about me you'll do this/look at this for me."

In my third example they're probably drowning or something and are trying to get someone's attention before that happens.

It's all very needful.

Defining someone drowning as needful is a lack of respect for human life. I feel that should be the exception to the rule. All other examples are good but the drowning took it one step too far.