How to assign unique id to swt widget and get it in swtbot?

Question 1

Unfortunately, there is no built-in way to do this.

I think your best option is to use the method Widget#setData(Object) to set the id.

You can generate a (pseudo) random id using:

UUID id = UUID.randomUUID();
widget.setData(id);

(or use any id generation method you want).

To find your widget, you would have to search through the children of the Shell (or the Composite to which you can narrow it down) with any search algorithm you want (DFS, BFS, ...) and then compare the UUID to the id you are searching for.

for(Control control : shell.getChildren())
{
    UUID id = (UUID) control.getData();

    if(id.equals(WHATEVER_HERE))
    {
        System.out.println(control);
    }
}

Question 2

In your Composite / UI part you set the data with the default SWT Bot Key or with your custom key

textOne.setData("org.eclipse.swtbot.widget.key", "textId1");
textTwo.setData("com.sample.my.custom.key", "textCustomId2");

In your SWTBot Test you can get the text as follows

// using the default SWTBot Key
botTextOne = bot.textWithId("textId1")

and

//using your custom key
botTextTwo = bot.textWithId("com.sample.my.custom.key", "textCustomId2")

References: