I'll take a shot at your question. But I'll warn you that I too am a beginner at this
Java stuff. That having been said, here goes!
The short response: A constructor can initialize values for the object being created.
Here's a long example...
Assume you've defined a class called Car.
In class Car you have defined three constructors. They might look something like this:
In another class you might have code that creates a Car object:
Each of these statements do three things.
1. They create a new variable (chevy and ford) of type Car. This is done by the two words on the left side of the assignment operator (the equals sign).
2. They each create a new Car object. This is done by the "new" operator which calls the appropriate Car() constructor in the class Car. The appropriate constructor is dictated by the number and type of arguments passed to the constructor. The Car constructor will initialize variables of the Car object (set the number of windows and set the color to either a specified color or to the default color, blue).
3. And finally, the assignment operator (the equals sign) will have the variables refer to the newly created objects.
So, your constructor has not only created an object, it also initialized some values to better define the object.
I'll bet someone more experienced than I could give a much better--and shorter--answer! But this might get you started. Now, look out for the notice about properly registering your name at the JavaRanch!