public boolean isIdentity() {
        if (x == 0 && y == 0 && z == 0 && w == 1) {
            return true;
        } else {
            return false;
        }
    }
Compares with the identity quaternion, without distinguishing -0 from 0.
The current instance is unaffected.

@return true if the current quaternion equals the identity, otherwise
    false
jme3-core/src/main/java/com/jme3/math/Quaternion.java