* java/io/ObjectInputStream.java (read): AND byte with 0xff to make
	result unsigned.
	(read (byte[], int, int)): Only call readNextBlock() if the block
	buffer would actually be overrun. Increment blockDataPosition.
	(callReadMethod): Propagate exceptions from invocation target.
	* java/io/ObjectOutputStream.java (callWriteMethod): Propagate
	exceptions from invocation target.

From-SVN: r39293