Mas Sulaiman, farmers in Java usually wore black trousers/shorts of the string draw style. Among farmers and other workers (I remember also carpenters o rtukang kayu) at least black is a practical colour. I'm not aware that there might be another reason for choosing the colour black. I don't remember anyone wearing a black shirt though. Usually everyone wore just a white T shirt from cotton. The iket used to be worn in the old days by most Javanese as far as I know. My Eyang Kakung (grandfather) who was the Lurah of our village, wore a batik iket around his head for everyday wear (also had his hair in a bun). When my brother and sister learned Javanese dancing, they used to wear everyday clothes. My brother in particular never took much notice of his appearance in his younger days ... hehe ... mind you he is very traditionally minded now and knows much more about tradition than I do, so I'll ask him and report back.