# Class SSLServerSocket

java.lang.Object
java.net.ServerSocket
javax.net.ssl.SSLServerSocket

All Implemented Interfaces:
  `Closeable, AutoCloseable`

public abstract class SSLServerSocket extends ServerSocket
This class extends `ServerSocket` and provides secure server sockets using protocols such as the Secure Sockets Layer (SSL) or Transport Layer Security (TLS) protocols.

Instances of this class are generally created using an `SSLServerSocketFactory`. The primary function of an `SSLServerSocket` is to create `SSLSocket`s by `accept`ing connections.

An `SSLServerSocket` contains several pieces of state data which are inherited by the `SSLSocket` at socket creation. These include the enabled cipher suites and protocols, whether client authentication is necessary, and whether created sockets should begin handshaking in client or server mode. The state inherited by the created `SSLSocket` can be overridden by calling the appropriate methods.

Since:
  1.4
See Also:
  - `ServerSocket`
  - `SSLSocket`

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `SSLServerSocket()`
  Used only by subclasses.
  `protected`
  `SSLServerSocket(int port)`
  Used only by subclasses.
  `protected`
  `SSLServerSocket(int port, int backlog)`
  Used only by subclasses.
  `protected`
  `SSLServerSocket(int port, int backlog, InetAddress address)`
  Used only by subclasses.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `abstract String[]`
  `getEnabledCipherSuites()`
  Returns the list of cipher suites which are currently enabled for use by newly accepted connections.
  `abstract String[]`
  `getEnabledProtocols()`
  Returns the names of the protocols which are currently enabled for use by the newly accepted connections.
  `abstract boolean`
  `getEnableSessionCreation()`
  Returns true if new SSL sessions may be established by the sockets which are created from this server socket.
  `abstract boolean`
  `getNeedClientAuth()`
  Returns true if client authentication will be required on newly `accept`ed server-mode `SSLSocket`s.
  `SSLParameters`
  `getSSLParameters()`
  Returns the SSLParameters in effect for newly accepted connections.
  `abstract String[]`
  `getSupportedCipherSuites()`
  Returns the names of the cipher suites which could be enabled for use on an SSL connection.
  `abstract String[]`
  `getSupportedProtocols()`
  Returns the names of the protocols which could be enabled for use.
  `abstract boolean`
  `getUseClientMode()`
  Returns true if accepted connections will be in SSL client mode.
  `abstract boolean`
  `getWantClientAuth()`
  Returns true if client authentication will be requested on newly accepted server-mode connections.
  `abstract void`
  `setEnabledCipherSuites(String[] suites)`
  Sets the cipher suites enabled for use by accepted connections.
  `abstract void`
  `setEnabledProtocols(String[] protocols)`
  Controls which particular protocols are enabled for use by accepted connections.
  `abstract void`
  `setEnableSessionCreation(boolean flag)`
  Controls whether new SSL sessions may be established by the sockets which are created from this server socket.
  `abstract void`
  `setNeedClientAuth(boolean need)`
  Controls whether `accept`ed server-mode `SSLSockets` will be initially configured to require client authentication.
  `void`
  `setSSLParameters(SSLParameters params)`
  Applies SSLParameters to newly accepted connections.
  `abstract void`
  `setUseClientMode(boolean mode)`
  Controls whether accepted connections are in the (default) SSL server mode, or the SSL client mode.
  `abstract void`
  `setWantClientAuth(boolean want)`
  Controls whether `accept`ed server-mode `SSLSockets` will be initially configured to request client authentication.

  ### Methods declared in class ServerSocket

  `accept, bind, bind, close, getChannel, getInetAddress, getLocalPort, getLocalSocketAddress, getOption, getReceiveBufferSize, getReuseAddress, getSoTimeout, implAccept, isBound, isClosed, setOption, setPerformancePreferences, setReceiveBufferSize, setReuseAddress, setSocketFactory, setSoTimeout, supportedOptions, toString`
  Modifier and Type
  Method
  Description
  `Socket`
  `accept()`
  Listens for a connection to be made to this socket and accepts it.
  `void`
  `bind(SocketAddress endpoint)`
  Binds the `ServerSocket` to a specific address (IP address and port number).
  `void`
  `bind(SocketAddress endpoint, int backlog)`
  Binds the `ServerSocket` to a specific address (IP address and port number).
  `void`
  `close()`
  Closes this socket.
  `ServerSocketChannel`
  `getChannel()`
  Returns the unique `ServerSocketChannel` object associated with this socket, if any.
  `InetAddress`
  `getInetAddress()`
  Returns the local address of this server socket.
  `int`
  `getLocalPort()`
  Returns the port number on which this socket is listening.
  `SocketAddress`
  `getLocalSocketAddress()`
  Returns the address of the endpoint this socket is bound to.
  `<T> T`
  `getOption(SocketOption<T> name)`
  Returns the value of a socket option.
  `int`
  `getReceiveBufferSize()`
  Gets the value of the `SO_RCVBUF` option for this `ServerSocket`, that is the proposed buffer size that will be used for Sockets accepted from this `ServerSocket`.
  `boolean`
  `getReuseAddress()`
  Tests if `SO_REUSEADDR` is enabled.
  `int`
  `getSoTimeout()`
  Retrieve setting for `SO_TIMEOUT`. 0 returns implies that the option is disabled (i.e., timeout of infinity).
  `protected final void`
  `implAccept(Socket s)`
  Subclasses of ServerSocket use this method to override accept() to return their own subclass of socket.
  `boolean`
  `isBound()`
  Returns the binding state of the ServerSocket.
  `boolean`
  `isClosed()`
  Returns the closed state of the ServerSocket.
  `<T> ServerSocket`
  `setOption(SocketOption<T> name, T value)`
  Sets the value of a socket option.
  `void`
  `setPerformancePreferences(int connectionTime, int latency, int bandwidth)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  This method was intended to allow for protocols that are now obsolete.
  `void`
  `setReceiveBufferSize(int size)`
  Sets a default proposed value for the `SO_RCVBUF` option for sockets accepted from this `ServerSocket`.
  `void`
  `setReuseAddress(boolean on)`
  Enable/disable the `SO_REUSEADDR` socket option.
  `static void`
  `setSocketFactory(SocketImplFactory fac)`
  Deprecated.
  Use a `ServerSocketFactory` and subclass `ServerSocket` directly.
  `void`
  `setSoTimeout(int timeout)`
  Enable/disable `SO_TIMEOUT` with the specified timeout, in milliseconds.
  `Set<SocketOption<?>>`
  `supportedOptions()`
  Returns a set of the socket options supported by this server socket.
  `String`
  `toString()`
  Returns the implementation address and implementation port of this socket as a `String`.

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected Object`
  `clone()`
  Creates and returns a copy of this object.
  `boolean`
  `equals(Object obj)`
  Indicates whether some other object is "equal to" this one.
  `protected void`
  `finalize()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Finalization is deprecated and subject to removal in a future release.
  `final Class<?>`
  `getClass()`
  Returns the runtime class of this `Object`.
  `int`
  `hashCode()`
  Returns a hash code value for this object.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `final void`
  `wait()`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  `final void`
  `wait(long timeoutMillis)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
  `final void`
  `wait(long timeoutMillis, int nanos)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

- ## Constructor Details

  - ### SSLServerSocket

    protected SSLServerSocket() throws IOException
    Used only by subclasses.

    Create an unbound TCP server socket using the default authentication context.

    Throws:
      `IOException` - if an I/O error occurs when creating the socket

  - ### SSLServerSocket

    protected SSLServerSocket(int port) throws IOException
    Used only by subclasses.

    Create a TCP server socket on a port, using the default authentication context. The connection backlog defaults to fifty connections queued up before the system starts to reject new connection requests.

    A port number of `0` creates a socket on any free port.

    Parameters:
      `port` - the port on which to listen
    Throws:
      `IOException` - if an I/O error occurs when creating the socket
      `IllegalArgumentException` - if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.

  - ### SSLServerSocket

    protected SSLServerSocket(int port, int backlog) throws IOException
    Used only by subclasses.

    Create a TCP server socket on a port, using the default authentication context and a specified backlog of connections.

    A port number of `0` creates a socket on any free port.

    The `backlog` argument is the requested maximum number of pending connections on the socket. Its exact semantics are implementation specific. In particular, an implementation may impose a maximum length or may choose to ignore the parameter altogether. The value provided should be greater than `0`. If it is less than or equal to `0`, then an implementation specific default will be used.

    Parameters:
      `port` - the port on which to listen
      `backlog` - requested maximum length of the queue of incoming connections.
    Throws:
      `IOException` - if an I/O error occurs when creating the socket
      `IllegalArgumentException` - if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.

  - ### SSLServerSocket

    protected SSLServerSocket(int port, int backlog, InetAddress address) throws IOException
    Used only by subclasses.

    Create a TCP server socket on a port, using the default authentication context and a specified backlog of connections as well as a particular specified network interface. This constructor is used on multihomed hosts, such as those used for firewalls or as routers, to control through which interface a network service is provided.

    A port number of `0` creates a socket on any free port.

    The `backlog` argument is the requested maximum number of pending connections on the socket. Its exact semantics are implementation specific. In particular, an implementation may impose a maximum length or may choose to ignore the parameter altogether. The value provided should be greater than `0`. If it is less than or equal to `0`, then an implementation specific default will be used.

    If address is null, it will default accepting connections on any/all local addresses.

    Parameters:
      `port` - the port on which to listen
      `backlog` - requested maximum length of the queue of incoming connections.
      `address` - the address of the network interface through which connections will be accepted
    Throws:
      `IOException` - if an I/O error occurs when creating the socket
      `IllegalArgumentException` - if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.

- ## Method Details

  - ### getEnabledCipherSuites

    public abstract String[] getEnabledCipherSuites()
    Returns the list of cipher suites which are currently enabled for use by newly accepted connections.

    If this list has not been explicitly modified, a system-provided default guarantees a minimum quality of service in all enabled cipher suites.

    Note that even if a suite is enabled, it may never be used. This can occur if the peer does not support it, or its use is restricted, or the requisite certificates (and private keys) for the suite are not available, or an anonymous suite is enabled but authentication is required.

    The returned array includes cipher suites from the list of standard cipher suite names in the JSSE Cipher Suite Names section of the Java Security Standard Algorithm Names Specification, and may also include other cipher suites that the provider supports.

    Returns:
      an array of cipher suites enabled
    External Specifications
      - Java Security Standard Algorithm Names
    See Also:
      - `getSupportedCipherSuites()`
      - `setEnabledCipherSuites(String[])`

  - ### setEnabledCipherSuites

    public abstract void setEnabledCipherSuites(String[] suites)
    Sets the cipher suites enabled for use by accepted connections.

    The cipher suites must have been listed by getSupportedCipherSuites() as being supported. Following a successful call to this method, only suites listed in the `suites` parameter are enabled for use.

    Suites that require authentication information which is not available in this ServerSocket's authentication context will not be used in any case, even if they are enabled.

    Note that the standard list of cipher suite names may be found in the JSSE Cipher Suite Names section of the Java Security Standard Algorithm Names Specification. Providers may support cipher suite names not found in this list or might not use the recommended name for a certain cipher suite.

    `SSLSocket`s returned from `accept()` inherit this setting.

    Parameters:
      `suites` - Names of all the cipher suites to enable
    Throws:
      `IllegalArgumentException` - when one or more of ciphers named by the parameter is not supported, or when the parameter is null.
    External Specifications
      - Java Security Standard Algorithm Names
    See Also:
      - `getSupportedCipherSuites()`
      - `getEnabledCipherSuites()`

  - ### getSupportedCipherSuites

    public abstract String[] getSupportedCipherSuites()
    Returns the names of the cipher suites which could be enabled for use on an SSL connection.

    Normally, only a subset of these will actually be enabled by default, since this list may include cipher suites which do not meet quality of service requirements for those defaults. Such cipher suites are useful in specialized applications.

    The returned array includes cipher suites from the list of standard cipher suite names in the JSSE Cipher Suite Names section of the Java Security Standard Algorithm Names Specification, and may also include other cipher suites that the provider supports.

    Returns:
      an array of cipher suite names
    External Specifications
      - Java Security Standard Algorithm Names
    See Also:
      - `getEnabledCipherSuites()`
      - `setEnabledCipherSuites(String[])`

  - ### getSupportedProtocols

    public abstract String[] getSupportedProtocols()
    Returns the names of the protocols which could be enabled for use.
    Returns:
      an array of protocol names supported
    See Also:
      - `getEnabledProtocols()`
      - `setEnabledProtocols(String[])`

  - ### getEnabledProtocols

    public abstract String[] getEnabledProtocols()
    Returns the names of the protocols which are currently enabled for use by the newly accepted connections.

    Note that even if a protocol is enabled, it may never be used. This can occur if the peer does not support the protocol, or its use is restricted, or there are no enabled cipher suites supported by the protocol.

    Returns:
      an array of protocol names
    See Also:
      - `getSupportedProtocols()`
      - `setEnabledProtocols(String[])`

  - ### setEnabledProtocols

    public abstract void setEnabledProtocols(String[] protocols)
    Controls which particular protocols are enabled for use by accepted connections.

    The protocols must have been listed by getSupportedProtocols() as being supported. Following a successful call to this method, only protocols listed in the `protocols` parameter are enabled for use.

    `SSLSocket`s returned from `accept()` inherit this setting.

    Parameters:
      `protocols` - Names of all the protocols to enable.
    Throws:
      `IllegalArgumentException` - when one or more of the protocols named by the parameter is not supported or when the protocols parameter is null.
    See Also:
      - `getEnabledProtocols()`
      - `getSupportedProtocols()`

  - ### setNeedClientAuth

    public abstract void setNeedClientAuth(boolean need)
    Controls whether `accept`ed server-mode `SSLSockets` will be initially configured to require client authentication.

    A socket's client authentication setting is one of the following:

    - client authentication required
    - client authentication requested
    - no client authentication desired

    Unlike `setWantClientAuth(boolean)`, if the accepted socket's option is set and the client chooses not to provide authentication information about itself, the negotiations will stop and the connection will be dropped.

    Calling this method overrides any previous setting made by this method or `setWantClientAuth(boolean)`.

    The initial inherited setting may be overridden by calling `SSLSocket.setNeedClientAuth(boolean)` or `SSLSocket.setWantClientAuth(boolean)`.

    Parameters:
      `need` - set to true if client authentication is required, or false if no client authentication is desired.
    See Also:
      - `getNeedClientAuth()`
      - `setWantClientAuth(boolean)`
      - `getWantClientAuth()`
      - `setUseClientMode(boolean)`

  - ### getNeedClientAuth

    public abstract boolean getNeedClientAuth()
    Returns true if client authentication will be required on newly `accept`ed server-mode `SSLSocket`s.

    The initial inherited setting may be overridden by calling `SSLSocket.setNeedClientAuth(boolean)` or `SSLSocket.setWantClientAuth(boolean)`.

    Returns:
      true if client authentication is required, or false if no client authentication is desired.
    See Also:
      - `setNeedClientAuth(boolean)`
      - `setWantClientAuth(boolean)`
      - `getWantClientAuth()`
      - `setUseClientMode(boolean)`

  - ### setWantClientAuth

    public abstract void setWantClientAuth(boolean want)
    Controls whether `accept`ed server-mode `SSLSockets` will be initially configured to request client authentication.

    A socket's client authentication setting is one of the following:

    - client authentication required
    - client authentication requested
    - no client authentication desired

    Unlike `setNeedClientAuth(boolean)`, if the accepted socket's option is set and the client chooses not to provide authentication information about itself, the negotiations will continue.

    Calling this method overrides any previous setting made by this method or `setNeedClientAuth(boolean)`.

    The initial inherited setting may be overridden by calling `SSLSocket.setNeedClientAuth(boolean)` or `SSLSocket.setWantClientAuth(boolean)`.

    Parameters:
      `want` - set to true if client authentication is requested, or false if no client authentication is desired.
    See Also:
      - `getWantClientAuth()`
      - `setNeedClientAuth(boolean)`
      - `getNeedClientAuth()`
      - `setUseClientMode(boolean)`

  - ### getWantClientAuth

    public abstract boolean getWantClientAuth()
    Returns true if client authentication will be requested on newly accepted server-mode connections.

    The initial inherited setting may be overridden by calling `SSLSocket.setNeedClientAuth(boolean)` or `SSLSocket.setWantClientAuth(boolean)`.

    Returns:
      true if client authentication is requested, or false if no client authentication is desired.
    See Also:
      - `setWantClientAuth(boolean)`
      - `setNeedClientAuth(boolean)`
      - `getNeedClientAuth()`
      - `setUseClientMode(boolean)`

  - ### setUseClientMode

    public abstract void setUseClientMode(boolean mode)
    Controls whether accepted connections are in the (default) SSL server mode, or the SSL client mode.

    Servers normally authenticate themselves, and clients are not required to do so.

    In rare cases, TCP servers need to act in the SSL client mode on newly accepted connections. For example, FTP clients acquire server sockets and listen there for reverse connections from the server. An FTP client would use an SSLServerSocket in "client" mode to accept the reverse connection while the FTP server uses an SSLSocket with "client" mode disabled to initiate the connection. During the resulting handshake, existing SSL sessions may be reused.

    `SSLSocket`s returned from `accept()` inherit this setting.

    Parameters:
      `mode` - true if newly accepted connections should use SSL client mode.
    See Also:
      - `getUseClientMode()`

  - ### getUseClientMode

    public abstract boolean getUseClientMode()
    Returns true if accepted connections will be in SSL client mode.
    Returns:
      true if the connection should use SSL client mode.
    See Also:
      - `setUseClientMode(boolean)`

  - ### setEnableSessionCreation

    public abstract void setEnableSessionCreation(boolean flag)
    Controls whether new SSL sessions may be established by the sockets which are created from this server socket.

    `SSLSocket`s returned from `accept()` inherit this setting.

    Parameters:
      `flag` - true indicates that sessions may be created; this is the default. false indicates that an existing session must be resumed.
    See Also:
      - `getEnableSessionCreation()`

  - ### getEnableSessionCreation

    public abstract boolean getEnableSessionCreation()
    Returns true if new SSL sessions may be established by the sockets which are created from this server socket.
    Returns:
      true indicates that sessions may be created; this is the default. false indicates that an existing session must be resumed
    See Also:
      - `setEnableSessionCreation(boolean)`

  - ### getSSLParameters

    public SSLParameters getSSLParameters()
    Returns the SSLParameters in effect for newly accepted connections. The ciphersuites and protocols of the returned SSLParameters are always non-null.
    Returns:
      the SSLParameters in effect for newly accepted connections
    Since:
      1.7
    See Also:
      - `setSSLParameters(SSLParameters)`

  - ### setSSLParameters

    public void setSSLParameters(SSLParameters params)
    Applies SSLParameters to newly accepted connections.

    This means:

    - If `params.getCipherSuites()` is non-null, `setEnabledCipherSuites()` is called with that value.
    - If `params.getProtocols()` is non-null, `setEnabledProtocols()` is called with that value.
    - If `params.getNeedClientAuth()` or `params.getWantClientAuth()` return `true`, `setNeedClientAuth(true)` and `setWantClientAuth(true)` are called, respectively; otherwise `setWantClientAuth(false)` is called.
    - If `params.getServerNames()` is non-null, the socket will configure its server names with that value.
    - If `params.getSNIMatchers()` is non-null, the socket will configure its SNI matchers with that value.
    Parameters:
      `params` - the parameters
    Throws:
      `IllegalArgumentException` - if the setEnabledCipherSuites() or the setEnabledProtocols() call fails
    Since:
      1.7
    See Also:
      - `getSSLParameters()`