GSSCredential

[Douglas Surber]

I understand the intent of modules. Let's go back to Java 8. Both java.sql.ConnectionBuilder and java.security.jgss.GSSCredential are part of Java SE. Before modules we would have thought nothing of adding this method to the JDBC standard (at least in regard to dependency on GSSCredential). Is the new module system so restrictive that it effectively disallows adding this method? I don't believe that is the case. 

  module java.sql {
    . . .
    requires static java.security.jgss; 
    . . .
  }

The above tells the JVM that java.security.jgss must be available to compile java.sql. This is interesting only when compiling Java SE which is not a typical user task. It does not require that java.security.jgss be available to compile or run code that requires java.sql. If a user wanted to call the method they would have to add

    requires java.security.jgss;

to their own module-info.java.

I do not consider this a reason not to include this method in JDBC.

Douglas



> On Jun 5, 2019, at 9:33 AM, Mark Rotteveel <mark at lawinegevaar.nl> wrote:
> 
> On 5-6-2019 17:57, Douglas Surber wrote:
>> I believe that even if this were added to the java.sql module, users of that module would not have to use java.security.jgss unless they actually used the method. java.security.jgss would not be required either to compile against java.sql or to execute code compiled against java.sql unless the method was used. Yes, compiling java.sql would require java.security,jgss, but using the compiled code either to build or execute would not.
>> Is my understanding correct?
>> And regardless of whether the above is correct, if we decide not to include this method in java.sql, how should this capability be exposed in standard way? Surely the move to modules is not so restrictive as to prevent exposing such a capability when all the types in question are present in Java SE.
> 
> The whole idea of modules is that you don't depend on the Java SE as a whole, but only on the modules that you really need. If you use modules, then you only get what you require.
> 
> I believe attempts to load implementations of this interface would probably fail if the module hasn't been declared as a required dependency, but I would need to experiment to confirm because I'm not that familiar with modules yet.
> 
> And for Java itself, attempts to compile `java.sql.ConnectionBuilder` or generate its Javadoc will fail without the module dependency declared in `java.sql`s `module-info.java`.
> 
> In other words, this addition might introduce additional headaches or otherwise additional module dependencies for java.sql, which the majority of drivers would not need otherwise. On the other hand, module `java.security.jgss` is pretty small.
> 
> The alternative would be to have a driver specific interface declaring the method, and the unwrapping/casting to that interface to set the property.
> 
> Mark
> 
> -- 
> Mark Rotteveel