RFR: 8325579: Inconsistent behavior in com.sun.jndi.ldap.Connection::createSocket

[Christoph Langer]

During analysing a customer case I figured out that we have an inconsistency between documentation and actual behavior in class com.sun.jndi.ldap.Connection. The [method documentation of com.sun.jndi.ldap.Connection::createSocket](https://github.com/openjdk/jdk/blob/3ebe6c192a5dd5cc46ae2d263713c9ff38cd46bb/src/java.naming/share/classes/com/sun/jndi/ldap/Connection.java#L281) states: "If a timeout is supplied but unconnected sockets are not supported then the timeout is ignored and a connected socket is created."

This, however does not happen. If a SocketFactory would not support unconnected sockets, it would likely throw a SocketException in [SocketFactory::createSocket()](https://github.com/openjdk/jdk/blob/6303c0e7136436a2d3cb6043b88edf788c0067cc/src/java.base/share/classes/javax/net/SocketFactory.java#L123). And since [the code](https://github.com/openjdk/jdk/blob/3ebe6c192a5dd5cc46ae2d263713c9ff38cd46bb/src/java.naming/share/classes/com/sun/jndi/ldap/Connection.java#L336) does not check for this behavior, a connection with timeout value through a SocketFactory that does not support unconnected sockets would simply fail with an IOException.

So we should either make the code adhere to what is documented or adapt the documentation to the actual behavior.

I hereby try to fix the connect coding. Alternatively, we could also adapt the description - I have no strong opinion. What do the experts suggest?

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Commit messages:
 - JDK-8325579

Changes: https://git.openjdk.org/jdk/pull/17797/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17797&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325579
  Stats: 38 lines in 1 file changed: 17 ins; 12 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/17797.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17797/head:pull/17797

PR: https://git.openjdk.org/jdk/pull/17797