Decoding the sequence
fd 93 a8 8c b9
with the charset UTF-8 with direct buffers gives

java.nio.BufferUnderflowException
at java.nio.Buffer.nextGetIndex(Buffer.java:492)
at java.nio.DirectByteBuffer.get(DirectByteBuffer.java:223)
at sun.nio.cs.UTF_8$Decoder.decodeBufferLoop(UTF_8.java:339)
at sun.nio.cs.UTF_8$Decoder.decodeLoop(UTF_8.java:378)
at java.nio.charset.CharsetDecoder.decode(CharsetDecoder.java:562)