In the api spec for java.awt.Rectangle.grow(int,int), it says,

"Modifies the rectangle so that it is h units larger on both the left and right size, and v units larger at both the top and bottom."
This has a typo - "size."

The next sentence of the doc states, "The new rectangle has (x-h,y-v) as its top-left corner, a width of x+2h and a height of y+2v."

However, according to the correctly working code, the new rectangle's width is the original width + 2h and the new rectangle's height is the original height + 2v.