public boolean isUnitVector() {
        float len = length();
        return 0.99f < len && len < 1.01f;
    }
Returns true if this vector is a unit vector (length() ~= 1),
returns false otherwise.

@return true if this vector is a unit vector (length() ~= 1),
or false otherwise.
jme3-core/src/main/java/com/jme3/math/Vector4f.java