Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Constants](https://developer.android.com/reference/java/net/SocketOptions#constants) \| [Methods](https://developer.android.com/reference/java/net/SocketOptions#pubmethods)

# SocketOptions


`
public


interface
SocketOptions
`


`


`

|---|
| java.net.SocketOptions |

|---|
| Known indirect subclasses [DatagramSocketImpl](https://developer.android.com/reference/java/net/DatagramSocketImpl), [SocketImpl](https://developer.android.com/reference/java/net/SocketImpl) |---|---| | [DatagramSocketImpl](https://developer.android.com/reference/java/net/DatagramSocketImpl) | Abstract datagram and multicast socket implementation base class. | | [SocketImpl](https://developer.android.com/reference/java/net/SocketImpl) | The abstract class `SocketImpl` is a common superclass of all classes that actually implement sockets. | |

<br />

*** ** * ** ***

Interface of methods to get/set socket options. This interface is
implemented by: **SocketImpl** and **DatagramSocketImpl**.
Subclasses of these should override the methods
of this interface in order to support their own options.


The methods and constants which specify options in this interface are
for implementation only. If you're not subclassing SocketImpl or
DatagramSocketImpl, **you won't use these directly.** There are
type-safe methods to get/set each of these options in Socket, ServerSocket,
DatagramSocket and MulticastSocket.

## Summary

| ### Constants ||
|---|---|
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#IP_MULTICAST_IF` Set which outgoing interface on which to send multicast packets. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#IP_MULTICAST_IF2` Same as above. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#IP_MULTICAST_LOOP` This option enables or disables local loopback of multicast datagrams. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#IP_TOS` This option sets the type-of-service or traffic class field in the IP header for a TCP or UDP socket. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_BINDADDR` Fetch the local address binding of a socket (this option cannot be "set" only "gotten", since sockets are bound at creation time, and so the locally bound address cannot be changed). |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_BROADCAST` Sets SO_BROADCAST for a socket. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_KEEPALIVE` When the keepalive option is set for a TCP socket and no data has been exchanged across the socket in either direction for 2 hours (NOTE: the actual value is implementation dependent), TCP automatically sends a keepalive probe to the peer. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_LINGER` Specify a linger-on-close timeout. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_OOBINLINE` When the OOBINLINE option is set, any TCP urgent data received on the socket will be received through the socket input stream. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_RCVBUF` Set a hint the size of the underlying buffers used by the platform for incoming network I/O. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_REUSEADDR` Sets SO_REUSEADDR for a socket. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_REUSEPORT` Sets SO_REUSEPORT for a socket. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_SNDBUF` Set a hint the size of the underlying buffers used by the platform for outgoing network I/O. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#SO_TIMEOUT` Set a timeout on blocking Socket operations: ``` ServerSocket.accept(); SocketInputStream.read(); DatagramSocket.receive(); ``` The option must be set prior to entering a blocking operation to take effect. |
| `int` | `https://developer.android.com/reference/java/net/SocketOptions#TCP_NODELAY` Disable Nagle's algorithm for this connection. |

| ### Public methods ||
|---|---|
| ` abstract https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/net/SocketOptions#getOption(int)(int optID) ` Fetch the value of an option. |
| ` abstract void` | ` https://developer.android.com/reference/java/net/SocketOptions#setOption(int,%20java.lang.Object)(int optID, https://developer.android.com/reference/java/lang/Object value) ` Enable/disable the option specified by *optID*. |

## Constants

### IP_MULTICAST_IF

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int IP_MULTICAST_IF
```

Set which outgoing interface on which to send multicast packets.
Useful on hosts with multiple network interfaces, where applications
want to use other than the system default. Takes/returns an InetAddress.


Valid for Multicast: DatagramSocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/MulticastSocket#setInterface(java.net.InetAddress)`
- `https://developer.android.com/reference/java/net/MulticastSocket#getInterface()`

Constant Value:

16
(0x00000010)


### IP_MULTICAST_IF2

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int IP_MULTICAST_IF2
```

Same as above. This option is introduced so that the behaviour
with IP_MULTICAST_IF will be kept the same as before, while
this new option can support setting outgoing interfaces with either
IPv4 and IPv6 addresses.

NOTE: make sure there is no conflict with this

<br />

**See also:**

- `https://developer.android.com/reference/java/net/MulticastSocket#setNetworkInterface(java.net.NetworkInterface)`
- `https://developer.android.com/reference/java/net/MulticastSocket#getNetworkInterface()`

Constant Value:

31
(0x0000001f)


### IP_MULTICAST_LOOP

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int IP_MULTICAST_LOOP
```

This option enables or disables local loopback of multicast datagrams.
This option is enabled by default for Multicast Sockets.

<br />

Constant Value:

18
(0x00000012)


### IP_TOS

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int IP_TOS
```

This option sets the type-of-service or traffic class field
in the IP header for a TCP or UDP socket.

<br />

Constant Value:

3
(0x00000003)


### SO_BINDADDR

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_BINDADDR
```

Fetch the local address binding of a socket (this option cannot
be "set" only "gotten", since sockets are bound at creation time,
and so the locally bound address cannot be changed). The default local
address of a socket is INADDR_ANY, meaning any local address on a
multi-homed host. A multi-homed host can use this option to accept
connections to only one of its addresses (in the case of a
ServerSocket or DatagramSocket), or to specify its return address
to the peer (for a Socket or DatagramSocket). The parameter of
this option is an InetAddress.


This option **must** be specified in the constructor.


Valid for: SocketImpl, DatagramSocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#getLocalAddress()`
- `https://developer.android.com/reference/java/net/DatagramSocket#getLocalAddress()`

Constant Value:

15
(0x0000000f)


### SO_BROADCAST

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_BROADCAST
```

Sets SO_BROADCAST for a socket. This option enables and disables
the ability of the process to send broadcast messages. It is supported
for only datagram sockets and only on networks that support
the concept of a broadcast message (e.g. Ethernet, token ring, etc.),
and it is set by default for DatagramSockets.

<br />

Constant Value:

32
(0x00000020)


### SO_KEEPALIVE

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_KEEPALIVE
```

When the keepalive option is set for a TCP socket and no data
has been exchanged across the socket in either direction for
2 hours (NOTE: the actual value is implementation dependent),
TCP automatically sends a keepalive probe to the peer. This probe is a
TCP segment to which the peer must respond.
One of three responses is expected:
1. The peer responds with the expected ACK. The application is not
notified (since everything is OK). TCP will send another probe
following another 2 hours of inactivity.
2. The peer responds with an RST, which tells the local TCP that
the peer host has crashed and rebooted. The socket is closed.
3. There is no response from the peer. The socket is closed.

The purpose of this option is to detect if the peer host crashes.

Valid only for TCP socket: SocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setKeepAlive(boolean)`
- `https://developer.android.com/reference/java/net/Socket#getKeepAlive()`

Constant Value:

8
(0x00000008)


### SO_LINGER

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_LINGER
```

Specify a linger-on-close timeout. This option disables/enables
immediate return from a **close()** of a TCP Socket. Enabling
this option with a non-zero Integer *timeout* means that a
**close()** will block pending the transmission and acknowledgement
of all data written to the peer, at which point the socket is closed
*gracefully*. Upon reaching the linger timeout, the socket is
closed *forcefully*, with a TCP RST. Enabling the option with a
timeout of zero does a forceful close immediately. If the specified
timeout value exceeds 65,535 it will be reduced to 65,535.


Valid only for TCP: SocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setSoLinger(boolean,%20int)`
- `https://developer.android.com/reference/java/net/Socket#getSoLinger()`

Constant Value:

128
(0x00000080)


### SO_OOBINLINE

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_OOBINLINE
```

When the OOBINLINE option is set, any TCP urgent data received on
the socket will be received through the socket input stream.
When the option is disabled (which is the default) urgent data
is silently discarded.

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setOOBInline(boolean)`
- `https://developer.android.com/reference/java/net/Socket#getOOBInline()`

Constant Value:

4099
(0x00001003)


### SO_RCVBUF

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_RCVBUF
```

Set a hint the size of the underlying buffers used by the
platform for incoming network I/O. When used in set, this is a
suggestion to the kernel from the application about the size of
buffers to use for the data to be received over the
socket. When used in get, this must return the size of the
buffer actually used by the platform when receiving in data on
this socket.

Valid for all sockets: SocketImpl, DatagramSocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setReceiveBufferSize(int)`
- `https://developer.android.com/reference/java/net/Socket#getReceiveBufferSize()`
- `https://developer.android.com/reference/java/net/DatagramSocket#setReceiveBufferSize(int)`
- `https://developer.android.com/reference/java/net/DatagramSocket#getReceiveBufferSize()`

Constant Value:

4098
(0x00001002)


### SO_REUSEADDR

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_REUSEADDR
```

Sets SO_REUSEADDR for a socket. This is used only for MulticastSockets
in java, and it is set by default for MulticastSockets.


Valid for: DatagramSocketImpl

<br />

Constant Value:

4
(0x00000004)


### SO_REUSEPORT

Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_REUSEPORT
```

Sets SO_REUSEPORT for a socket. This option enables and disables
the ability to have multiple sockets listen to the same address
and port.


Valid for: SocketImpl, DatagramSocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/StandardSocketOptions#SO_REUSEPORT`

Constant Value:

14
(0x0000000e)


### SO_SNDBUF

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_SNDBUF
```

Set a hint the size of the underlying buffers used by the
platform for outgoing network I/O. When used in set, this is a
suggestion to the kernel from the application about the size of
buffers to use for the data to be sent over the socket. When
used in get, this must return the size of the buffer actually
used by the platform when sending out data on this socket.

Valid for all sockets: SocketImpl, DatagramSocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setSendBufferSize(int)`
- `https://developer.android.com/reference/java/net/Socket#getSendBufferSize()`
- `https://developer.android.com/reference/java/net/DatagramSocket#setSendBufferSize(int)`
- `https://developer.android.com/reference/java/net/DatagramSocket#getSendBufferSize()`

Constant Value:

4097
(0x00001001)


### SO_TIMEOUT

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int SO_TIMEOUT
```

Set a timeout on blocking Socket operations:

```
ServerSocket.accept();
SocketInputStream.read();
DatagramSocket.receive();
```

The option must be set prior to entering a blocking
operation to take effect. If the timeout expires and the
operation would continue to block,
**java.io.InterruptedIOException** is raised. The Socket is
not closed in this case.

Valid for all sockets: SocketImpl, DatagramSocketImpl

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setSoTimeout(int)`
- `https://developer.android.com/reference/java/net/ServerSocket#setSoTimeout(int)`
- `https://developer.android.com/reference/java/net/DatagramSocket#setSoTimeout(int)`

Constant Value:

4102
(0x00001006)


### TCP_NODELAY

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final int TCP_NODELAY
```

Disable Nagle's algorithm for this connection. Written data
to the network is not buffered pending acknowledgement of
previously written data.


Valid for TCP only: SocketImpl.

<br />

**See also:**

- `https://developer.android.com/reference/java/net/Socket#setTcpNoDelay(boolean)`
- `https://developer.android.com/reference/java/net/Socket#getTcpNoDelay()`

Constant Value:

1
(0x00000001)


## Public methods

### getOption

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract Object getOption (int optID)
```

Fetch the value of an option.
Binary options will return java.lang.Boolean.TRUE
if enabled, java.lang.Boolean.FALSE if disabled, e.g.:

```
SocketImpl s;
...
Boolean noDelay = (Boolean)(s.getOption(TCP_NODELAY));
if (noDelay.booleanValue()) {
    // true if TCP_NODELAY is enabled...
...
}
```


For options that take a particular type as a parameter,
getOption(int) will return the parameter's value, else
it will return java.lang.Boolean.FALSE:

```
Object o = s.getOption(SO_LINGER);
if (o instanceof Integer) {
    System.out.print("Linger time is " + ((Integer)o).intValue());
} else {
  // the true type of o is java.lang.Boolean.FALSE;
}
```

<br />

<br />

| Parameters ||
|---|---|
| `optID` | `int`: an `int` identifying the option to fetch <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the value of the option <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/net/SocketException` | if the socket is closed |
| `https://developer.android.com/reference/java/net/SocketException` | if *optID* is unknown along the protocol stack (including the SocketImpl) |

**See also:**

- `https://developer.android.com/reference/java/net/SocketOptions#setOption(int,%20java.lang.Object)`

### setOption

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract void setOption (int optID, 
                Object value)
```

Enable/disable the option specified by *optID*. If the option
is to be enabled, and it takes an option-specific "value", this is
passed in *value*. The actual type of value is option-specific,
and it is an error to pass something that isn't of the expected type:

```
 SocketImpl s;
 ...
 s.setOption(SO_LINGER, new Integer(10));
    // OK - set SO_LINGER w/ timeout of 10 sec.
 s.setOption(SO_LINGER, new Double(10));
    // ERROR - expects java.lang.Integer
```
If the requested option is binary, it can be set using this method by a java.lang.Boolean:   

```
 s.setOption(TCP_NODELAY, Boolean.TRUE);
    // OK - enables TCP_NODELAY, a binary option
 
```

Any option can be disabled using this method with a Boolean.FALSE:   

```
 s.setOption(TCP_NODELAY, Boolean.FALSE);
    // OK - disables TCP_NODELAY
 s.setOption(SO_LINGER, Boolean.FALSE);
    // OK - disables SO_LINGER
 
```

For an option that has a notion of on and off, and requires a non-boolean parameter, setting its value to anything other than *Boolean.FALSE* implicitly enables it.   
Throws SocketException if the option is unrecognized, the socket is closed, or some low-level error occurred   

<br />

<br />

| Parameters ||
|---|---|
| `optID` | `int`: identifies the option <br /> |
| `value` | `Object`: the parameter of the socket option <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/net/SocketException` | if the option is unrecognized, the socket is closed, or some low-level error occurred |

**See also:**

- `https://developer.android.com/reference/java/net/SocketOptions#getOption(int)`