Created attachment 87152 [details]
Test loading XML document with client-side InputStreamToXInputStreamAdapter

In main/javaunohelper/com/sun/star/lib/uno/adapter/InputStreamToXInputStreamAdapter.java there are bugs that result in java.lang.NullPointerException when a stream is passed across the inter-process UNO bridge, and the remote end tries to call the local readBytes() or readSomeBytes().

The UNO documentation for XInputStream::readBytes() documents how the buffer argument, of type sequence, is an "out" parameter, and isn't passed to the implementing end, which is why we get the buffer as a 2 dimensional array "byte[][] b" and b[0] == null. Its role is to box a 1 dimensional byte[] array to be returned the client. Thus, those methods need to allocate the buffer if it is missing or too small.

Additionally, virtually all other readBytes() and readSomeBytes() implementations trim this sequence to the actual number of bytes read. This presumably reduces the inter-process network traffic, but some callers even rely on the sequence to be trimmed, eg. main/sax/source/expatwrap/xml2utf.cxx. Thus our returned array should be trimmed too.

The attached code can be used to reproduce the issue. You'll need to link to these too:
juh.jar   jurt.jar  ridl.jar  unoil.jar
and it reads /var/tmp/1.xml. I've added a delay in the code to allow debugging, and it will print "BAD read..." instead of crashing.