Support JDK Tools lacking ToolProvider services

[sormuras]

Compare the list of tool specifications

https://docs.oracle.com/en/java/javase/15/docs/specs/man/

with the list of 8 tools provided by JDK 16-ea

• jar (provided by module jdk.jartool@16-ea)
• javac (provided by module jdk.compiler@16-ea)
• javadoc (provided by module jdk.javadoc@16-ea)
• javap (provided by module jdk.jdeps@16-ea)
• jdeps (provided by module jdk.jdeps@16-ea)
• jlink (provided by module jdk.jlink@16-ea)
• jmod (provided by module jdk.jlink@16-ea)
• jpackage (provided by module jdk.jpackage@16-ea)

Especially jarsigner is missing here.

0. Which could be provided by module jdk.jartool itself.
1. Bach should provide a ToolProvider calling JarSigner in-process.
2. In the meantime, Bach could also support running external programs via the ProcessBuilder API.

[sormuras]

0. https://mail.openjdk.java.net/pipermail/security-dev/2021-February/024296.html