java-stream-player | OGG VORBIS , FLAC , MONKEY 's AUDIO and SPEEX audio formats | Audio Utils library

AudioInputStream.skip does not support negative arguments. If you read the Javadoc of InputStream.skip it says (emphasis mine):

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, the skip method for class InputStream always returns 0, and no bytes are skipped. Subclasses may handle the negative value differently.

It does mention that subclasses may change this behavior but the documentation of AudioInputStream does not give any indication it does this.

Class (AudioInputStream) javadoc:

An audio input stream is an input stream with a specified audio format and length. The length is expressed in sample frames, not bytes. Several methods are provided for reading a certain number of bytes from the stream, or an unspecified number of bytes. The audio input stream keeps track of the last byte that was read. You can skip over an arbitrary number of bytes to get to a later position for reading. An audio input stream may support marks. When you set a mark, the current position is remembered so that you can return to it later.

The AudioSystem class includes many methods that manipulate AudioInputStream objects. For example, the methods let you:

• obtain an audio input stream from an external audio file, stream, or URL
• write an external file from an audio input stream
• convert an audio input stream to a different audio format

AudioInputStream.skip javadoc:

Skips over and discards a specified number of bytes from this audio input stream.

This method will always skip an integral number of frames. If n does not specify an integral number of frames, a maximum of n - (n % frameSize) bytes will be skipped.

Also, if you look at the implementation of AudioInputStream.skip you can see that the second if statement immediately returns 0 if n is <= 0.