Documentation for FileLock.release() says that ClosedChannelException should be thrown when the channel that was used to acquire the lock is no longer open.

Exception used to be thrown in previous builds (b79 and so). But this build doesnt throw it.

java version "1.4.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta3-b80)
Java HotSpot(TM) Client VM (build 1.4.0-beta3-b80, mixed mode)

import java.io.*;
import java.nio.channels.*;
import java.nio.*;

public class Release {

     public static void main(String[] args) throws Exception {
        Release tests = new Release();
        tests.go();
     }

    public boolean go() throws Exception {
        boolean bReturn = true;
        RandomAccessFile raf = null;
        FileChannel c = null;
        File tempFile = new File("blahTemp");
        try {
           raf = new RandomAccessFile(tempFile,"rw");
           c = raf.getChannel();
           FileLock fl1 = c.lock(0,c.size(),true);
           c.close();
           try {
             fl1.release();
             bReturn = false;
             System.out.println("Test Failed!");
           }catch(ClosedChannelException e){
             e.printStackTrace();
             System.out.println("Test Passed!");
           }
        } catch (Exception e) {
           bReturn = false;
           e.printStackTrace();
        }
        return bReturn;
    }
}