What are java equivalents to JS push, concat, unshift?

java, javascript

Solution

This looks like you are trying to use a ByteBuffer to serialize some data.

 public static void serialize(ByteBuffer bb, String r, String s) {
      bb.put(48);
      int start = bb.position();
      bb.put(0); // padding.
      bb.put(2);
      byte[] rBa = r.getBytes();
      bb.put((byte) rBa.length);
      bb.put(rBa);
      byte[] sBa = s.getBytes();
      bb.put((byte) sBa.length);
      bb.put(sBa);
      bb.put(start, (byte) (bb.position() - start - 1));
}

Using an `List<Byte>` is very inefficient and not supported by the packages which do IO.

Problem

I'm trying to convert the following `JS` to `Java`: ``` serializeSig:function(r,s){ var rBa=r.toByteArraySigned(); var sBa=s.toByteArraySigned(); var sequence=[]; sequence.push(2); sequence.push(rBa.length); sequence=sequence.concat(rBa); sequence.push(2); sequence.push(sBa.length); sequence=sequence.concat(sBa); sequence.unshift(sequence.length); sequence.unshift(48); return sequence } ``` I think `push` would translate to `add`, concat to some kind of `addAll`, but what is `unshift`? And of what type would my variables in java be?

Original source