Print tree using asterisk

[Sumatra]

I'm new to Java and I hardly know anything about it. One of my first assignments is to print a tree using asterisk(*) like this:
*
* *
* *
*** ***

***

I hope that came out right. My question is how do you write an application that prints this out?

[Sumatra]

Tree doesn't look like a tree ^ but I hope you know what I mean (triangle shape asterisk tree)