Java: Double Value Comparison

Question

Do we need to be careful when comparing a double value against zero?

if ( someAmount <= 0){
.....
}

Answer 1

Check a double or float value is 0, an error threshold is used to detect if the value is near 0, but not quite 0. I think this method is the best what I met.

How to test if a double is zero? Answered by @William Morrison

public boolean isZero(double value, double threshold){
  return value >= -threshold && value <= threshold;
}

For example, set threshold as 0. like this,

System.out.println(isZero(0.00, 0));
System.out.println(isZero(0, 0));
System.out.println(isZero(0.00001, 0));

The results as true, true and false from above example codes.

Have Fun @.@