" I can't get the syntax right"
In general, we ask to see your best attempt...
But I will just paste a code fragment of one of my programs, hopefully, it can get you started.

1.     final int BUFFER_SIZE = 4096; // You can adjust this
   
2.     String fileNameIn = "G:/Tmp/LargeImage.jpg";
3. 
   
4.     byte[] buffer = new byte[BUFFER_SIZE];
5.     InputStream in = null;
6.     try
7.     {
8.       in = new BufferedInputStream(new FileInputStream(fileNameIn));
9.       int n = in.read(buffer, 0, BUFFER_SIZE);
10.       while (n > 0)
11.       {
12.         // Use buffer here
    
13.         n = in.read(buffer, 0, BUFFER_SIZE);
14.       }
15.     }
16.     catch (IOException e)
17.     {
18.       System.out.println("Error: " + e);
19.     }
20.     finally
21.     {
22.       try
23.       {
24.         if (in != null)
25.           in.close();
26.       }
27.       catch (IOException e)
28.       {
29.         System.out.println("Error on close: " + e);
30.       }
31.     }

Thanks phi.lho, I would have posted code but was going in so many different directions I didn't know what would be helpful.  Trying your example, I get the same issue as from my code: it seems to read in fine but it only returns the buffer size as an int (in your example 4096, in mine 4).

Here's my code:

1. String filename = "/Users/jeffthompson/Documents/Processing/ReadBinaryFile/data/test-1min.wav";
   BufferedInputStream s;
   byte[] buffer = new byte[4];
   
   void setup() {
   
     try {
       s = new BufferedInputStream(new FileInputStream(filename));
       int bytesRead = 0;  
   
       while ( (bytesRead = s.read (buffer)) != -1) {    // so long as we haven't reached the end of the file (-1)
         println(bytesRead);
       }
     }
     catch (IOException e) {
       println("ERROR!");
     }
   
     exit();
   }

The first four bytes of a .wav file should be (when converted to ASCII) "RIFF".  Should be 52 49 46 46 in hex.

Here's a "Processing-ified" version of your code:

1. final int BUFFER_SIZE = 4;
   
   String fileNameIn = "/Users/jeffthompson/Documents/Processing/ReadBinaryFile/data/test-1min.wav";
   byte[] buffer = new byte[BUFFER_SIZE];
   InputStream in = null;
   
   void setup() {
   
     try {
       in = new BufferedInputStream(new FileInputStream(fileNameIn));
       int n = in.read(buffer, 0, BUFFER_SIZE);
   
       // read in 4 bytes
       n = in.read(buffer, 0, BUFFER_SIZE);
       println(n);  // print the data
       in.close();
     }
     catch (IOException e) {
       System.out.println("Error: " + e);
     }
     finally {
       try {
         if (in != null) {
           in.close();
         }
       }
       catch (IOException e) {
         System.out.println("Error on close: " + e);
       }
     }
    
     exit();
   }
   

When printing the result I get 4.

I have a feeling that I'm misunderstanding how this all works - BufferedReaders make a lot of sense but reading binary files... I just can't quite get it.

Ok, I can get it to return the correct hex values and it seems to work great:

1. // file to load
   String filename = "/Users/jeffthompson/Documents/Processing/ReadBinaryFile/data/test-1min.wav";
   int chunksToRead;                      // how many chunks to read out
   int bufferSize = 4;                    // how many bytes to load at a time (.wav is 4-byte chunks)
   
   byte[] buffer = new byte[bufferSize];  // read values into this buffer
   int tempVal;                           // temporary value to store incoming data
   InputStream input = null;              // stream itself (to input data from file)
   
   
   void setup() {
   
     // open stream
     try {
       input = new BufferedInputStream(new FileInputStream(filename));  // start stream
     }
     catch (IOException e) {
       println("Error: " + e);  // let us know if there are problems...
     }
   
     for (int i=0; i<chunksToRead; i++) {
       try {
         int n = input.read(buffer, 0, bufferSize);  // where to read from, offset, how many bytes
       }
   
       // if we have any errors, close and give us details
       catch (IOException e) {
         println("Error: " + e);
       }
   
       // read the data back
       // http://stackoverflow.com/questions/1026761/how-to-convert-a-byte-array-to-its-numeric-value-java
       for (int j=0; j<bufferSize; j++) {
         print(hex(buffer[j]) + " ");
         tempVal += (buffer[j] & 0xff) << (bufferSize * j);          // least significant byte first
         // tempVal = (tempVal << bufferSize) + (buffer[j] & 0xff);  // most significant byte first
       }
       println("= " + tempVal);                                      // display the values
       tempVal = 0;                                                  // reset value
     }
   
     // quit when done
     try {
       input.close();             // close the stream first...
     }
     catch (IOException e) {
       println("Error closing stream: " + e);   
     }
     exit();
   }
   

However, I can't seem to get the byte array to cast into an integer value that seems correct.  Various online calculators and sources don't give results that agree.

I found this via StackOverflow for Little Endian (wav format):

1. tempVal += (buffer[j] & 0xff) << (bufferSize * j);

But the values returned are often too large for the .wav format.  Any suggestions?

Shouldn't it be tempVal += (buffer[j] & 0xff) << (8 * j);?