public boolean isUnitVector() {
        float len = length();
        return 0.99f < len && len < 1.01f;
    }
Tests for a unit vector, with 1% tolerance. The current instance is
unaffected.

@return true if the current vector's length is between 0.99 and 1.01
    inclusive, otherwise false
jme3-core/src/main/java/com/jme3/math/Vector3f.java