Thread: Getting error on equals method for objects

I'm taking an introduction to java class right now, so please don't advice me to something that I have not learned yet. My assignment is that I have to create a class that has two fields. One called length and the other width. I have to make a method that returns the tract area. Similarly, I also have to make a method that indicates whether two objects have the same fields. Here is the code that I have assembled...so far

// create private fields to hold width and length
private double width;
private double length;
 
//create a constructor that initialized the value
public LandTract(double wid, double len)
{
 
width=wid;
length=len;
}
 
// this method will check to see if two object have same data stored in or
//not
public Boolean objectEqualChecker(LandTract object)
{
boolean flag;
if(length.equals(object.length) && width.equals(object.width))
{
flag=true;
}
}

My problem is encountered when writing that equals method

if(length.equals(object.length) && width.equals(object.width))

, I get an error saying

HTML Code:

cannot invoke equals(double) on the primitive type double

. Meanwhile, I do see, to realize that when I change my fields to capital "Double." The problem disappears; however, in my class I have never dealt with a situation where I have to use capital d in double. In fact, I don't even know what's the difference between Double and double. I do know what double is but not the other one...thanks in advance! for taking your time to read this