If you're hiding a variable name, which you're doing here by using the same name in the parameter list as in the class, you need to use this to remove ambiguity.
For example, the following code prints correctly:
The output is "Testing 1-2-3", as expected. However, if we remove the "this" keyword, as in the following code:
The output here is "null". Why? Because
Java tried to assign "this.title" to "this.title" because it didn't know which "title" the assignment wanted to use for the right value!
By the way, the original code also had two capitalization errors, "Public" for "public" and "Class" for "class". Java cares about such things.
Give a man a fish, he'll eat for one day. Teach a man to fish, he'll drink all your beer.
Cheers, Jeff (SCJP 1.4 all those years ago...)