javac recognize "10" and "1.10" as a valid arguments for the -source and -target options and 10 as a valid argument for the --release option.
Initially, the "10" arguments will just be aliases for 9 until 10-specific features are added later in the release.
With a new JDK release, new source and target values are needed in
Add javac options -source 10 -source 1.10 -target 10 -target 1.10
-source 1.10 The compiler accepts code with features introduced in Java SE 10.
-source 10 Synonym for 1.10.
-target 1.10 The compiler outputs class files appropriate for the 10 platform.
-target 10 Synonym for 1.10.
The default source and target is also updated from 9 to 10.