Cannot acquire overlapping shared locks.

Specification for FileLock says "A shared lock prevents other concurrently-running programs from acquiring an overlapping exclusive lock,
but does allow them to acquire overlapping shared locks."
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
import java.io.*;
import java.nio.channels.*;

public class FCLock {
     public static void main(String[] args) throws Exception {
        FCLock tests = new FCLock();
        tests.lockTest();
     }
    public boolean lockTest() throws Exception {
        boolean[] bReturn = {true};
        RandomAccessFile raf = null;
        FileChannel c = null;
        File tempFile = new File("blahTemp");
        tempFile.deleteOnExit();
        initTestFile(tempFile);
        try {
           raf = new RandomAccessFile(tempFile,"rw");
           c = raf.getChannel();
           T t = new T(c,bReturn);
           FileLock fl = c.lock(0,c.size(),true);
           System.out.println("Main Thread: Obtained file lock."+fl.toString());
           t.start();
           while(t.isAlive()) ; //Wait till t is dead.
        } catch (Exception e) {
           bReturn[0] = false;
           e.printStackTrace();
        }
        return bReturn[0];
    }

   /**
     * Creates file blah:
     */
    private void initTestFile(File blah) throws Exception {
        FileOutputStream fos = new FileOutputStream(blah);
        BufferedWriter awriter
            = new BufferedWriter(new OutputStreamWriter(fos, "8859_1"));
        for(int i=0; i<4000; i++) {
            String number = new Integer(i).toString();
            for (int h=0; h<4-number.length(); h++)
                awriter.write("0");
            awriter.write(""+i);
            awriter.newLine();
        }
       awriter.flush();
       awriter.close();
    }
} // Class FCLock

class T extends Thread {
   FileChannel fc;
   boolean[] result;

   public T(FileChannel c,boolean[] result){
   this.fc = c;
   this.result = result;
   }

   public void run(){
     System.out.println("T: Run started");
     FileLock flock = null;
     try {
       flock = fc.lock(0,fc.size(),true);
       System.out.println("T: TEST PASS. Obtained file lock . "+flock);
     } catch(OverlappingFileLockException e){
       result[0] = false;
       System.out.println("T: TEST FAIL.could not acquire shared lock on overlaping shared lock.");
     }
     catch(Exception e){
       result[0] = false;
       e.printStackTrace();
     }
  }
}


Same is the case when tryLock is used instead of lock().