This bug was found by St.Petersburg Java SQE team (by Stanislav Avzan).

The java.io.SequenceInputStream.read(buf,pos,len) works wrong if
len=0. It always skips to the end of sequence and returns -1 instead
of returning 0.
But Java Language Specification clearly states:
"If len is zero, then no bytes are read and 0 is returned; otherwise, there is
an attempt to read at least one byte. If no byte is available because the
stream is at end of file, the value -1 is returned; otherwise, at least one byte
is read and stored into b." (see p. 22.3.3)
Here is the simple example:
-----Test.java----------------
import java.io.*;

public class Test {

   public static void main( String[] argv ) {
     StringBufferInputStream is = new StringBufferInputStream("\0");
     StringBufferInputStream is2 = new StringBufferInputStream("\1");
     try {
       SequenceInputStream sis = new SequenceInputStream(is,is2);
       byte[] bb = new byte[5];
       int b = sis.read(bb,0,0); // either
       System.out.println("Here shouldn't be -1: "+b);
     } catch(Throwable e) {
       System.out.println("Test failed: unexpected <"+e+"> thrown");
     }
   }
}
-----Output-------------------
Here shouldn't be -1: -1
------------------------------

The error could be semply seen from source code:

    public int read(byte buf[], int pos, int len) throws IOException {
if (in == null) {
return -1;
}
int n = in.read(buf, pos, len);
if (n <= 0) {
nextStream();
return read(buf, pos, len);
}
return n;
    }

The correction would be as below:

  int n = in.read(buf, pos, len);
! if (n < 0) {
nextStream();