public boolean renameFile(File oldFile,File newFile){
synchronized (fileCache) {
    if (oldFile.renameTo(newFile)) {
      validateFileCache();
      return true;
    }
    return false;
  }
}

public boolean renameFile ( File oldFile , File newFile ) { synchronized ( fileCache ) { if ( oldFile . renameTo ( newFile ) ) { validateFileCache ( ) ; return true ; } return false ; } }
renames a file in the underlying file system .
