RFR: 8159855: Create an SPI for tools

[Mandy Chung]

This SPI is useful and provides as a replacement to existing use of internal APIs to launch some of our tools.  We will get jar, jmod, jlink and possibly other tools to convert to this SPI.

ToolProvider::findFirst(String name) can find tool providers on classpath.  I think it needs to wrap the for-loop (specifically iterating on providers) with doPrivileged due to the stack-based permission check.

Otherwise, looks good.

Mandy

> On Oct 4, 2016, at 4:46 PM, Jonathan Gibbons <jonathan.gibbons at oracle.com> wrote:
> 
> Resend with non-mostly-empty subject line!
> 
> -- Jon
> 
> On 10/04/2016 04:39 PM, Jonathan Gibbons wrote:
>> Core-libs folk,
>> 
>> Please review the following change to add a new service provider class
>>    java.util.spi.ToolProvider
>> 
>> which can be used provide simple "command-line" access to select JDK
>> tools, without starting a new JVM.
>> 
>> The following tools are updated to provide access through the new SPI:
>>    javac, javadoc, javap, jdeps
>> 
>> It is expected that additional tools will also be updated to provide access,
>> but that will be done separately.
>> 
>> Compiler-dev folk may wish to review the changes to the langtools repository.
>> 
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8159855
>> Webrev: http://cr.openjdk.java.net/~jjg/8159855/webrev.03/
>> API: http://cr.openjdk.java.net/~jjg/8159855/api.02/java/util/spi/ToolProvider.html
>> 
>> -- Jon
>