WHAT IS ADAT LAW ?

Adat law or adat recht in dutch, is some term that usually use for the name of common law in indonesian literature, how ever "we" not only indonesian but also student in law faculty had been misconception about it. We need some term of behaviour that can be named by adat law, not all behavior but some spesific are.

Van Vollenhoven said that
in indonesia he found 19 area that used the adat law, but his conception about it was diferent he studied the people on the area and write all behaviour of the people and named it by adat law. Ter Haar means adat law by the punishment of judge that created in term of people who used his own way of life or law.

I can't explain more about two different conception that they built but when i heard about adat law or adat recht then the meaning is :

1. There must be some behaviour in spesific people and spesific area.
2. It need the rutinity and continous of behaviour not just one time but forever as long as the people that believe it behavior still live, not mean every day but every certain time. 
3. Then this or those behaviours that they ussually doing, they do it with the perception that this is good behaviour then it must be done.
4. It has "opinio necessitatis" or faith that if the people not doing that behaviour correctly than they believe something bad will be happen as the punishment for that people.

or the simple way to understand about the adat law is the behaviours of the people that ussually doing it  that contain opinio necessitatis in faith.