解決java.lang.IllegalArgumentException: Comparison method violates its general contract!

java.lang.IllegalArgumentException: Comparison method violates its general contract!

Collection.sort with comparator .

comprator return mult 1 or -1 not 0

.....

if(o1.getA().equas(o2.getA()){

return 1;

}

if(o1.getA().equas(o2.getA()){

return -11;

}

...