IndexOutOfBounds Exception - scala

Question

I'm trying a small program that would read a file, convert that to a array of bytes and zip the bytes and return the zipped bytes back as an array. However, I'm getting IndexOutOfBounds thrown. Here is what I have so far tried!
private def getBytePayload(): Array[Byte] = {
val inputJson: String = Source.fromURL(getClass.getResource("/small_json.txt")).mkString
val bin: ByteArrayInputStream = new ByteArrayInputStream(inputJson.getBytes())
val bos: ByteArrayOutputStream = new ByteArrayOutputStream()
println("The unCompressed stream size is = " + inputJson.size) // Prints 5330
val gzip: GZIPOutputStream = new GZIPOutputStream(bos)
val buff = new Array[Byte](1024)
var len = 0
while((len = bin.read(buff)) != -1) {
gzip.write(buff, 0, len) // java.lang.IndexOutOfBoundsException is thrown!
}
println("The compressed stream size is = " + bos.toByteArray.size)
bos.toByteArray
}
Any pointers as to what has gone wrong?

Answer 1

As far as what the problem is, I'm not exactly sure. However, the following code should be revealing. See what it it tells you:
val buff = new Array[Byte](1024)
var len = 0
while((len = bin.read(buff)) != -1) {
//Print out actual contents of buff:
for(int i = 0; i < buff.length; i++) {
System.out.print(i + "=" + buff[i] + ", ");
}
System.out.println();
gzip.write(buff, 0, len) // java.lang.IndexOutOfBoundsException is thrown!
}
This is just my style-opinion, but I personally find this confusing
while((len = bin.read(buff)) != -1) {
and would change it to
len = bin.read(buff);
while(len != -1) {
//do stuff
len = bin.read(buff);
}