Initial batch of enhancements and fixes for enabling build functionality

Author: ajaychandran

example/migrating/javalib/1-maven-complete/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:17

example/migrating/javalib/2-maven-incomplete/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:17

example/migrating/javalib/2-maven-incomplete/build.mill

@@ -8,10 +8,10 @@
 
 > ./mill init
 converting Maven build
-writing Mill build file to fastexcel-writer/package.mill
-writing Mill build file to fastexcel-reader/package.mill
-writing Mill build file to e2e/package.mill
-writing Mill build file to build.mill
+writing fastexcel-writer/package.mill
+writing fastexcel-reader/package.mill
+writing e2e/package.mill
+writing build.mill
 init completed, run "mill resolve _" to list available tasks
 
 > ./mill -k __.compile # Compilation needs manual tweaking to pass

example/migrating/javalib/3-maven-complete-large/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:21

example/migrating/javalib/3-maven-complete-large/build.mill

@@ -6,8 +6,6 @@
 
 > ./mill init
 
-> echo 21 > .mill-jvm-version # Repo needs Java >=21 to build and test
-
 > rm twin/src/test/java/com/iluwatar/twin/BallThreadTest.java # skip flaky test
 > rm actor-model/src/test/java/com/iluwatar/actor/ActorModelTest.java # skip flaky test
 

example/migrating/javalib/4-gradle-complete/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:17

example/migrating/javalib/5-gradle-incomplete/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:17

example/migrating/javalib/5-gradle-incomplete/build.mill

@@ -4,10 +4,11 @@
 > git remote add -f origin https://github.com/mockito/mockito.git
 > git checkout v5.19.0 # multi-module Java project
 
-> ./mill init --gradle-jvm-id 17  # imported modules are not fully functional
+> ./mill init  # imported modules are not fully functional
 converting Gradle build
 init completed, run "mill resolve _" to list available tasks
 
-> ./mill mockito-core.compile   # module jvmId needs tweaking
-error: java.lang.UnsupportedClassVersionError: com/google/errorprone/ErrorProneJavacPlugin has been compiled by a more recent version...
+> ./mill mockito-core.compile   # Compilation needs manual tweaking to pass
+error: mockito-core/src/main/java/module-info.java:8:17
+module not found: net.bytebuddy
 */

example/migrating/scalalib/1-sbt-complete/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:17

example/migrating/scalalib/2-sbt-incomplete/.mill-jvm-version

@@ -0,0 +1 @@
+zulu:17