I did a test run with --illegal-access=deny to identify tests that will need to be updated in advance of making this the default. There are many javac tests failing that will need attention:
tools/javac/DefiniteAssignment/T8204610.java
tools/javac/T7093325.java
tools/javac/T8222949/TestConstantDynamic.java
tools/javac/cast/intersection/IntersectionTypeCastTest.java
tools/javac/classwriter/ExtraAttributes.java
tools/javac/defaultMethods/static/hiding/InterfaceMethodHidingTest.java
tools/javac/defaultMethods/super/TestDefaultSuperCall.java
tools/javac/failover/CheckAttributedTree.java
tools/javac/generics/diamond/7046778/DiamondAndInnerClassTest.java
tools/javac/generics/inference/8176534/TestUncheckedCalls.java
tools/javac/generics/rawOverride/7062745/GenericOverrideTest.java
tools/javac/lambda/FunctionalInterfaceConversionTest.java
tools/javac/lambda/LambdaParserTest.java
tools/javac/lambda/MethodReferenceParserTest.java
tools/javac/lambda/TestInvokeDynamic.java
tools/javac/lambda/TestLambdaToMethodStats.java
tools/javac/lambda/bytecode/TestLambdaBytecode.java
tools/javac/lambda/deduplication/ClassFieldDeduplication.java
tools/javac/lambda/mostSpecific/StructuralMostSpecificTest.java
tools/javac/lambda/typeInference/combo/TypeInferenceComboTest.java
tools/javac/multicatch/7030606/DisjunctiveTypeWellFormednessTest.java
tools/javac/multicatch/7030606/DisjunctiveTypeWellFormednessTest.java tier1
tools/javac/plugin/InternalAPI.java
tools/javac/resolve/BitWiseOperators.java
tools/javac/varargs/7042566/T7042566.java
tools/javac/varargs/warning/Warn4.java
tools/javac/varargs/warning/Warn5.java