Question

In J2ME to create the Display class object we use

private Display d;
d=Display.getDisplay(this);

What is this as parameter?

I know this refers to the current instance but when I write the following I get errors

d=Display.getDisplay(new MyClassName());

When I saw in book the method was written like below

static Display getDisplay(MIDlet midlet)

So then I tried this

MIDlet m;
d=Display.getDisplay(m);

But I am getting errors and I cannot even pass new MIDlet() as parameter since it’s an abstract class.

Answer 1

As Android says, this in d=Display.getDisplay(this); refers to your MIDlet.

But when you write the following you get errors

d=Display.getDisplay(new MyClassName());   

It’s because you try to create MIDlet by it’s constructor. You would to see MIDlet doc:

protected MIDlet()
Protected constructor for subclasses. The application management software is responsible for creating MIDlets and creation of MIDlets
is restricted. MIDlets should not attempt to create other MIDlets.
Throws:
SecurityException – unless the application management software is creating the MIDlet.