[GROOVY-9596] Cannot access protected field of Java superclass with --illegal-access=deny

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.4, 2.5.12
• Fix Version/s: 5.0.0-alpha-1
• Component/s: bytecode
• Environment: JDK 14 ; Groovy 2.5.12 or 3.0.4
• Assignee: Unassigned
• Reporter: Kevin Rushforth
• Created: 17/Jun/20 16:55
• Updated: 24/Jul/23 17:23
• Resolved: 13/Jul/22 16:24

Description

When using the Java option --illegal-access=deny, a Groovy subclass that extends a Java superclass in the Java runtime (e.g., a class in the java.base module) cannot access a protected field in the parent class using this.fieldName.

To reproduce this bug, use JDK 14 (or later) and run the following using either Groovy 2.5.12 or 3.0.4:

$ groovyc Main.groovy MyFilterReader.groovy
$ _JAVA_OPTIONS="--illegal-access=deny" groovy Main

It works correctly without --illegal-access=deny. You can add -Dsun.reflect.debugModuleAccessChecks=access to get more detailed information about the illegal access exceptions that are being swallowed by Groovy.

$ _JAVA_OPTIONS="--illegal-access=deny -Dsun.reflect.debugModuleAccessChecks=access" groovy Main

WORKAROUND: change the following line in the Groovy subclass:

line = ((BufferedReader)this.in).readLine();

to:

line = ((BufferedReader)super.in).readLine();

Issue Links

• is related to: GROOVY-9144 Fix warning "An illegal reflective access operation has occurred"
• relates to: GROOVY-10070 Groovy classes (for Groovy < 4) cannot access protected methods from base classes under Java 16