Program: 64201
Project: 64201
Buggy source:
/** 
 * Delete the file(s).
 * @exception BuildException if an error occurs
 */
public void execute() throws BuildException {
  if (usedMatchingTask) {
    log("String_Node_Str" + "String_Node_Str");
  }
  if (file == null && dir == null && filesets.size() == 0 && rcs.size() == 0) {
    throw new BuildException("String_Node_Str" + "String_Node_Str" + "String_Node_Str");
  }
  if (quiet && failonerror) {
    throw new BuildException("String_Node_Str" + "String_Node_Str",getLocation());
  }
  if (file != null) {
    if (file.exists()) {
      if (file.isDirectory()) {
        log("String_Node_Str" + file.getAbsolutePath() + "String_Node_Str"+ "String_Node_Str");
      }
 else {
        log("String_Node_Str" + file.getAbsolutePath());
        if (!delete(file)) {
          String message="String_Node_Str" + file.getAbsolutePath();
          if (failonerror) {
            throw new BuildException(message);
          }
 else {
            log(message,quiet ? Project.MSG_VERBOSE : Project.MSG_WARN);
          }
        }
      }
    }
 else {
      log("String_Node_Str" + file.getAbsolutePath() + "String_Node_Str",Project.MSG_VERBOSE);
    }
  }
  if (dir != null && dir.exists() && dir.isDirectory() && !usedMatchingTask) {
    if (verbosity == Project.MSG_VERBOSE) {
      log("String_Node_Str" + dir.getAbsolutePath());
    }
    removeDir(dir);
  }
  Path p=new Path(getProject());
  p.addAll(rcs);
  for (int i=0; i < filesets.size(); i++) {
    FileSet fs=(FileSet)filesets.get(i);
    p.add(includeEmpty ? new BCFileSet(fs) : fs);
  }
  if (usedMatchingTask && dir != null) {
    FileSet implicit=getImplicitFileSet();
    p.add(includeEmpty ? new BCFileSet(implicit) : implicit);
  }
  Restrict exists=new Restrict();
  exists.add(EXISTS);
  exists.add(p);
  Sort s=new Sort();
  s.add(REVERSE_FILESYSTEM);
  s.add(exists);
  String errorMessage=null;
  try {
    for (Iterator iter=s.iterator(); iter.hasNext(); ) {
      FileResource r=(FileResource)iter.next();
      if (!(r.isDirectory()) || r.getFile().list().length == 0) {
        log("String_Node_Str" + r,verbosity);
        if (!delete(r.getFile())) {
          errorMessage="String_Node_Str" + (r.isDirectory() ? "String_Node_Str" : "String_Node_Str") + r;
        }
      }
    }
  }
 catch (  Exception e) {
    errorMessage=e.getMessage();
  }
  if (errorMessage != null) {
    if (failonerror) {
      throw new BuildException(errorMessage);
    }
    log(errorMessage,quiet ? Project.MSG_VERBOSE : Project.MSG_WARN);
  }
}

Fixed version (ground truth):
/** 
 * Delete the file(s).
 * @exception BuildException if an error occurs
 */
public void execute() throws BuildException {
  if (usedMatchingTask) {
    log("String_Node_Str" + "String_Node_Str");
  }
  if (file == null && dir == null && filesets.size() == 0 && rcs == null) {
    throw new BuildException("String_Node_Str" + "String_Node_Str" + "String_Node_Str");
  }
  if (quiet && failonerror) {
    throw new BuildException("String_Node_Str" + "String_Node_Str",getLocation());
  }
  if (file != null) {
    if (file.exists()) {
      if (file.isDirectory()) {
        log("String_Node_Str" + file.getAbsolutePath() + "String_Node_Str"+ "String_Node_Str");
      }
 else {
        log("String_Node_Str" + file.getAbsolutePath());
        if (!delete(file)) {
          handle("String_Node_Str" + file.getAbsolutePath());
        }
      }
    }
 else {
      log("String_Node_Str" + file.getAbsolutePath() + "String_Node_Str",Project.MSG_VERBOSE);
    }
  }
  if (dir != null && dir.exists() && dir.isDirectory() && !usedMatchingTask) {
    if (verbosity == Project.MSG_VERBOSE) {
      log("String_Node_Str" + dir.getAbsolutePath());
    }
    removeDir(dir);
  }
  Resources resourcesToDelete=new Resources();
  resourcesToDelete.setProject(getProject());
  Resources filesetDirs=new Resources();
  filesetDirs.setProject(getProject());
  for (int i=0; i < filesets.size(); i++) {
    FileSet fs=(FileSet)filesets.get(i);
    resourcesToDelete.add(fs);
    if (includeEmpty) {
      filesetDirs.add(new ReverseDirs(fs.getDir(),fs.getDirectoryScanner().getIncludedDirectories()));
    }
  }
  if (usedMatchingTask && dir != null) {
    FileSet implicit=getImplicitFileSet();
    resourcesToDelete.add(implicit);
    if (includeEmpty) {
      filesetDirs.add(new ReverseDirs(dir,implicit.getDirectoryScanner().getIncludedDirectories()));
    }
  }
  resourcesToDelete.add(filesetDirs);
  if (rcs != null) {
    Restrict exists=new Restrict();
    exists.add(EXISTS);
    exists.add(rcs);
    Sort s=new Sort();
    s.add(REVERSE_FILESYSTEM);
    s.add(exists);
    resourcesToDelete.add(s);
  }
  try {
    if (resourcesToDelete.isFilesystemOnly()) {
      for (Iterator iter=resourcesToDelete.iterator(); iter.hasNext(); ) {
        FileResource r=(FileResource)iter.next();
        if (!r.isExists()) {
          continue;
        }
        if (!(r.isDirectory()) || r.getFile().list().length == 0) {
          log("String_Node_Str" + r,verbosity);
          if (!delete(r.getFile()) && failonerror) {
            handle("String_Node_Str" + (r.isDirectory() ? "String_Node_Str" : "String_Node_Str") + r);
          }
        }
      }
    }
 else {
      handle(getTaskName() + "String_Node_Str");
    }
  }
 catch (  Exception e) {
    handle(e);
  }
}