RFR: 8235139: Remove the socket impl factory mechanism

[Daniel Fuchs]

On Wed, 3 Feb 2021 11:03:51 GMT, Patrick Concannon <pconcannon at openjdk.org> wrote:

> Hi,
> 
> Could someone please review my proposed changeset for JDK-8235139: '`Remove the socket impl factory mechanism`' ?
> 
> These changes propose to deprecate (for the eventual removal) the API points for statically configuring a system-wide factory for the `Socket`, `ServerSocket`, and `DatagramSocket` types in the `java.net package`. Specifically, the following:
> 
> **Methods**:
> - `static void Socket.setSocketImplFactory​(SocketImplFactory fac)`
> - `static void ServerSocket.setSocketFactory​(SocketImplFactory fac)`
> - `static void DatagramSocket.setDatagramSocketImplFactory​(DatagramSocketImplFactory fac)`
> 
> **Types**:
> - `java.net SocketImplFactory`
> - `java.net DatagramSocketImplFactory`
> 
> The CSR for[ JDK-8220494](https://bugs.openjdk.java.net/browse/JDK-8220494) contains some verbiage about the potential
> issues that setting factories can have, and alludes to their possible
> future removal. 
> 
> Kind regards,
> Patrick

Changes requested by dfuchs (Reviewer).

src/java.base/share/classes/java/net/Socket.java line 546:

> 544:     @SuppressWarnings("deprecation")
> 545:     void setImpl() {
> 546:         SocketImplFactory factory = Socket.factory;

The scope of `@SuppressWarnings` should be reduced as much as possible. I believe in this case it can be reduced to the assignation of the factory:

        @SuppressWarnings("deprecation")
        SocketImplFactory factory = Socket.factory;

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PR: https://git.openjdk.java.net/jdk/pull/2375