How can I play audio instantly in Java?

Question

I know JavaSound API like this:

audioInputStream = AudioSystem.getAudioInputStream(file);
AudioFormat audioFormat = audioInputStream.getFormat();
DataLine.Info info = new Info(SourceDataLine.class, audioFormat);
sourceDataLine = (SourceDataLine) AudioSystem.getLine(info);
sourceDataLine.open();
sourceDataLine.start();
floatVoiceControl.setValue(-20);
byte[] buf = new byte[0xFF];
int onceReadDataSize = 0;

While file is the File object.

But when I tried to play some very small audio very frequently (say, the audio played when a small enemy is killed), it blocks my main thread and make the game very slow.
Is there any alternative or workarounds? I prefer something inside the Java's standard library, since I'm developing a game engine based on Swing.

Answer 1

From the code you provide it is not discernible if you run the sound on your main-thread or on a worker thread. I will just assume that you are using a ThreadPoolExecutor or similar so you don't have to expensively create a new thread every time you want to play some sound.

From reading the Javadoc of the DataLine Interface I understad that the start() method you use in line #6 of your codesample initiates some I/O operations for reading the audiodata from the underlying file:

Allows a line to engage in data I/O.

^{Excerpt from the javadoc of the start() method}

Digging further into the javax soundAPI sources we find that the implementation of AudioSystem.getAudioInputStream(File) works with a list of AudioFileReaders for which there are no known implementations, which means without knowing what sort of audio-file you're trying to load we cannot reasonably dig any much further.

---

Conclusion:

From our research into the APIs and sources, and from your statement that:

But when I tried to play some very small audio very frequently...

^{emphasis mine}

We can reasonably assume that you're getting limited by I/O operation limitations. You might want to see if you can load the sound-file into the heap and play it from memory instead of playing it from disk.