The common BOMs are :

Encoding	Representation (hexadecimal)	Representation (decimal)
UTF-8	EF BB BF	239 187 191
UTF-16 (BE)	FE FF	254 255
UTF-16 (LE)	FF FE	255 254
UTF-32 (BE)	00 00 FE FF	0 0 254 255
UTF-32 (LE)	FF FE 00 00	255 254 0 0

The sample code

public class Bom{

  public static void main(String[] args) throws Exception{

    String text = "this is text body";
    byte[] tbyte = text.getBytes("UTF-8");

    FileOutputStream fos = new FileOutputStream("bom.txt");
    fos.write(239);
    fos.write(187);
    fos.write(191);
    fos.write(tbyte);
    fos.close();
  }
}

Reference:

程序员永远的痛之字符编码的奥秘

http://www.rgagnon.com/javadetails/java-handle-utf8-file-with-bom.html

https://community.oracle.com/thread/1263222

http://blog.csdn.net/tu_bingbing/article/details/7988735