how to use ByteArrayOutputStream and DataOutputStream simultaneously (Java)

Question

I\'m having quite a problem here, and I think it is because I don\'t understand very much how I should use the API provided by Java.

I need to write an int

Answer 1

Like this:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream w = new DataOutputStream(baos);

w.writeInt(100);
w.write(byteArray);

w.flush();

byte[] result = baos.toByteArray();

Actually your second version will not work at all. DataOutputStream requires an actual target stream in which to write the data. You can't do new DataOutputStream(). There isn't actually any constructor like that.