The Java binary wrapper script works around command line length limits by creating a jar file with a Class-Path manifest entry containing the long classpath (related: #6289).

JDK 9 adds support for flag files using the @argument-file syntax, see "java Command-Line Argument Files" in https://docs.oracle.com/javase/9/tools/java.htm.

We should use that instead of the manifest jar hack when targeting JDK 9.

We could back-fill support for that syntax for older --javabase versions by adding logic to the wrapper script.