Local variables which is binded by a proc is not garbage collected, if the proc is passed to java function.

Environment

jruby 9.1.0.0 (2.3.0) 2016-05-02 a633c63 Java HotSpot(TM) 64-Bit Server VM 25.151-b12 on 1.8.0_151-b12 +jit [mswin32-x86_64]

Expected Behavior

JavaClass.java

public class JavaClass
{
    public JavaClass(Runnable proc)
    {
        proc.run();
    }
}

memoryleak.rb

import 'JavaClass'

class BigClass
    # 100MB class
    def initialize
        @a = "a" * (100 * 1024 ** 2)
    end
end

def func
    a = BigClass.new
    JavaClass.new do
        puts "callback"
    end
end

func

# GC by Java VisualVM

gets

$ javac JavaClass.java
$ jruby-9.0.5.0/bin/jruby memoryleak.rb

run GC by jvisualvm

after running GC, memory usage is reduced about 100MB.

Actual Behavior

$ javac JavaClass.java
$ jruby-9.1.0.0/bin/jruby memoryleak.rb (9.1.0.0 or above)

run GC by jvisualvm

after running GC, memory usage is not reduced.