question: public long length ( ) { try { long len = fileLength ; if ( SysProperties . CHECK2 ) { len = file . size ( ) ; if ( len != fileLength ) { DbException . throwInternalError ( "file " + name + " length " + len + " expected " + fileLength ) ; } } if ( SysProperties . CHECK2 && len % Constants . FILE_BLOCK_SIZE != 0 ) { long newLength = len + Constants . FILE_BLOCK_SIZE - ( len % Constants . FILE_BLOCK_SIZE ) ; file . truncate ( newLength ) ; fileLength = newLength ; DbException . throwInternalError ( "unaligned file length " + name + " len " + len ) ; } return len ; } catch ( IOException e ) { throw DbException . convertIOException ( e , name ) ; } }
target:  Get the file size in bytes.