Problem 1:
For the FE_FLOATING_POINT_EQUALITY issue, you should not be comparing two float values directly with the == operator, since due to tiny rounding errors, the values might be semantically “equal” for your application even if the condition value1 == value2 does not hold true.
In order to fix this, modify your code as follows:
private boolean equals(final Quantity other) {
return (Math.abs(this.mAmount - convertedAmount(other)) < EPSILON);
}
Where EPSILON is a constant that you should define in your code, and represents small differences that are acceptable to your application, e.g. .0000001.
Problem 2:
For the EQ_COMPARETO_USE_OBJECT_EQUALS issue: It is strongly recommended that wherever x.compareTo(y) returns zero, x.equals(y) should be true. In your code you have implemented compareTo, but you have not overriden equals, so you are inheriting the implementation of equals from Object, and the above condition is not met.
In order to fix this, override equals (and perhaps hashCode) in your class, so that when x.compareTo(y) returns 0, then x.equals(y) will return true.