45  * @implNote The JDK historically used a {@code SocketImpl} implementation named

    45  * @implNote Client and server sockets created with the {@code Socket} and

    46  * <em>PlainSocketImpl</em>. This has been replaced by a newer implementation

    46  * {@code SocketServer} public constructors create a system/platform default

    47  * but the JDK continues to ship with the older implementation to allow code that

    47  * {@code SocketImpl}. The JDK historically used a {@code SocketImpl}

    48  * depends on unspecified behavior, that differs between the old and new

    48  * implementation type named "PlainSocketImpl" that has since been replaced by a

    49  * implementations, to continue to run. The old implementation will be used if

    49  * newer implementation. The JDK continues to ship with the older implementation

    50  * the Java virtual machine is started with the system property {@systemProperty

    50  * to allow code to run that depends on unspecified behavior that differs between

    51  * jdk.net.usePlainSocketImpl} set on the command line. The value of the system

    51  * the old and new implementations. The old implementation will be used if the

    52  * property is the string representation of a boolean. If set without a value

    52  * Java virtual machine is started with the system property {@systemProperty

    53  * then it defaults to {@code true}, hence running with {@code

    53  * jdk.net.usePlainSocketImpl} set on the command line. It may also be set in

    54  * -Djdk.net.usePlainSocketImpl} or {@code -Djdk.net.usePlainSocketImpl=true}

    54  * the JDK's network configuration file, located in {@code

    55  * will configure the Java virtual machine use the old implementation.

    55  * ${java.home}/conf/net.properties}, for cases where it needs to be set without

    56  * changing the command line. The value of the system property is the string

    57  * representation of a boolean. If set without a value then it defaults to {@code

    58  * true}, hence running with {@code -Djdk.net.usePlainSocketImpl} or {@code

    59  * -Djdk.net.usePlainSocketImpl=true} will configure the Java virtual machine

    60  * to use the old implementation.