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does javafx has built in audio capture?

I know there is a duplicate question right here, but it's obsolete, so does javafx support audio capture.
Does it have any audio capturing API or interfaces, i know of AudioClip in javafx.scene.media. but it's only for playback.

No, JavaFX 8 does not have an audio capture API.
There is an existing feature request (currently scheduled for implementation in Java 9):
JDK-8090438 Camera and Microphone
For now, you can use the existing javax.sound API (which will probably work just fine from a JavaFX application), as suggested in Robin Jonsson's coment.

How to read and play realtime sound stream in java?

I'm using Java to read and play some real time audio streams such as the voice from radio station.
I have the real time web address like this one and it can be played in a web browser.
How can I play it using Java language?
Thanks.

MP3SPI is a Java Service Provider Interface that adds MP3 (MPEG 1/2/2.5 Layer 1/2/3) audio format support for Java Platform. It supports streaming, ID3v2 frames, Equalizer etc. It is based on JLayer and Tritonus Java libraries.
You can use this library MP3 SPI for Java Sound , and its documentation here.
Library reference

Android Multitrack Audio Library?

Hi Guys I am trying to build a "4-track" recording app on Android.
I'm looking for a library or set of classes I can use record audio and mix 4 channels of audio to a 2 channel "mixdown".
Ideally it would be similar to the javax.sound.sampled library.
Low latency is also important...
I am new to Android development and have only worked in web dev for a year (c#, jquery, sql, vb).

You will likely have to do an implementation of AudioTrack. This will give you the most control.
Ref:
http://developer.android.com/reference/android/media/AudioTrack.html
Android: Mixing multiple AudioTrack instances?

Java get barcode informaton from barcode scanner

I have been searching for this. All the related Java APIs are worked on images. They get the information from barcode contained in the images and print barcode to images.
My question is how to get the barcode directly from the scanner in Java? Is there any API I am missing to read barcode directly from scanner? Or, whether I need to generate in-memory image from the information got by the scanner?

AFAIK, most of barcode scanners have keyboard emulation mode. You can attach scanner to your PC, scan the barcode and scanner will provide you with barcode information emulating ordinary keypresses which you can capture in any acceptable way (e.g. as keypresslistener or inputfield in Java Swing)

Most of modern barcode scanners can be set up to work in serial emulation mode. If you set them up this way, you can communicate with the device as if you are communicating with a normal serial port (read/write). Then you can use a Java library for communicating with the serial device. I used a library called RxTx (http://rxtx.qbang.org/wiki/index.php/Main_Page) which worked great both on Windows and on Linux.

Playing Live streamed audio through Java

Are there any java libraries out there that can handle live streamed audio such as an internet radio stream that can then be played back using Java?
I've looked into stuff like Xuggler/FFMpeg but I'm not sure if they can handle the fact that I'm just trying to play a live stream.
It would have to be able to handle most/all of the formats that internet radio stations usually stream in.
Thanks a lot.

You can have a look at JMF - Java Media Framework
http://en.wikipedia.org/wiki/Java_Media_Framework
http://www.oracle.com/technetwork/java/javase/tech/index-jsp-140239.html
On the Wikipedia site is also a list of alternatives:
Freedom for Media in Java (FMJ) An API-compatible with JMF alternative !
JavaSound
QuickTime for Java
IBM Toolkit for MPEG-4
Jffmpeg
jvlc
vlcj
gstreamer-java
Cortado, a complete player for Ogg Vorbis and Theora in a Java applet
Directshow <> Java Wrapper
Fobs4JMF
JLayer MP3 library
Xuggler
Video4Linux4Java