RandomAccessFile

Constructs a new RandomAccessFile based on file and opens it according to the access string in mode .

mode may have one of following values:

Constructs a new RandomAccessFile based on the file named fileName and opens it according to the access string in mode . The file path may be specified absolutely or relative to the system property "user.dir" .

Closes this file.

Gets this file's FileChannel object.

The file channel's position is the same as this file's file pointer offset (see getFilePointer() ). Any changes made to this file's file pointer offset are also visible in the file channel's position and vice versa.

Gets this file's FileDescriptor . This represents the operating system resource for this random access file.

Gets the current position within this file. All reads and writes take place at the current file pointer position.

Returns the length of this file in bytes.

Reads up to byteCount bytes from the current position in this file and stores them in the byte array buffer starting at byteOffset . Blocks until at least one byte has been read, the end of the file is detected, or an exception is thrown. Returns the number of bytes actually read or -1 if the end of the stream has been reached. See also readFully(byte[]) .

Reads bytes from the current position in this file and stores them in the byte array buffer . The maximum number of bytes read corresponds to the size of buffer . Blocks until at least one byte has been read, the end of the file is detected, or an exception is thrown. Returns the number of bytes actually read or -1 if the end of the file has been reached. See also readFully(byte[]) .

Reads a single byte from the current position in this file and returns it as an integer in the range from 0 to 255. Returns -1 if the end of the file has been reached. Blocks until one byte has been read, the end of the file is detected, or an exception is thrown.

Reads a boolean from the current position in this file. Blocks until one byte has been read, the end of the file is reached or an exception is thrown.

Reads an 8-bit byte from the current position in this file. Blocks until one byte has been read, the end of the file is reached or an exception is thrown.

Reads a big-endian 16-bit character from the current position in this file. Blocks until two bytes have been read, the end of the file is reached or an exception is thrown.

Reads a big-endian 64-bit double from the current position in this file. Blocks until eight bytes have been read, the end of the file is reached or an exception is thrown.

Reads a big-endian 32-bit float from the current position in this file. Blocks until four bytes have been read, the end of the file is reached or an exception is thrown.

Equivalent to readFully(dst, 0, dst.length); .

Reads byteCount bytes from this stream and stores them in the byte array dst starting at offset . If byteCount is zero, then this method returns without reading any bytes. Otherwise, this method blocks until byteCount bytes have been read. If insufficient bytes are available, EOFException is thrown. If an I/O error occurs, IOException is thrown. When an exception is thrown, some bytes may have been consumed from the stream and written into the array.

Reads a big-endian 32-bit integer from the current position in this file. Blocks until four bytes have been read, the end of the file is reached or an exception is thrown.

Reads a line of text form the current position in this file. A line is represented by zero or more characters followed by '\n' , '\r' , "\r\n" or the end of file marker. The string does not include the line terminating sequence.

Blocks until a line terminating sequence has been read, the end of the file is reached or an exception is thrown.

Reads a big-endian 64-bit long from the current position in this file. Blocks until eight bytes have been read, the end of the file is reached or an exception is thrown.

Reads a big-endian 16-bit short from the current position in this file. Blocks until two bytes have been read, the end of the file is reached or an exception is thrown.

Reads a string that is encoded in modified UTF-8 from this file. The number of bytes that must be read for the complete string is determined by the first two bytes read from the file. Blocks until all required bytes have been read, the end of the file is reached or an exception is thrown.

Reads an unsigned 8-bit byte from the current position in this file and returns it as an integer. Blocks until one byte has been read, the end of the file is reached or an exception is thrown.

Reads an unsigned big-endian 16-bit short from the current position in this file and returns it as an integer. Blocks until two bytes have been read, the end of the file is reached or an exception is thrown.

Moves this file's file pointer to a new position, from where following read , write or skip operations are done. The position may be greater than the current length of the file, but the file's length will only change if the moving of the pointer is followed by a write operation.

Sets the length of this file to newLength . If the current file is smaller, it is expanded but the contents from the previous end of the file to the new end are undefined. The file is truncated if its current size is bigger than newLength . If the current file pointer position is in the truncated part, it is set to the end of the file.

Skips over count bytes in this file. Less than count bytes are skipped if the end of the file is reached or an exception is thrown during the operation. Nothing is done if count is negative.

Writes a byte to this file, starting at the current file pointer. Only the least significant byte of the integer oneByte is written.

Writes byteCount bytes from the byte array buffer to this file, starting at the current file pointer and using byteOffset as the first position within buffer to get bytes.

Writes the entire contents of the byte array buffer to this file, starting at the current file pointer.

Writes a boolean to this file as a single byte (1 for true, 0 for false), starting at the current file pointer.

Writes an 8-bit byte to this file, starting at the current file pointer. Only the least significant byte of the integer val is written.

Writes the low order 8-bit bytes from a string to this file, starting at the current file pointer.

Writes a big-endian 16-bit character to this file, starting at the current file pointer. Only the two least significant bytes of the integer val are written, with the high byte first.

Writes big-endian 16-bit characters from str to this file, starting at the current file pointer.

Writes a big-endian 64-bit double to this file, starting at the current file pointer. The bytes are those returned by doubleToLongBits(double) , meaning a canonical NaN is used.

Writes a big-endian 32-bit float to this file, starting at the current file pointer. The bytes are those returned by floatToIntBits(float) , meaning a canonical NaN is used.

Writes a big-endian 32-bit integer to this file, starting at the current file pointer.

Writes a big-endian 64-bit long to this file, starting at the current file pointer.

Writes a big-endian 16-bit short to this file, starting at the current file pointer. Only the two least significant bytes of the integer val are written.

Writes a string encoded with modified UTF-8 to this file, starting at the current file pointer.

Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable ), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.