A small jruby program that slams the PermGen

bug_test.rb

class BugTest
  def run
    puts "Hey"
  end
end

# Wait so I can attach VisualVM to inspect
puts "Press enter to begin"
gets

i = 1

while true
  e = Java::RealData.new
  
  # Every instance of BugTest creates a new class in a ClassLoader that doesn't get garbage collected
  e.setErrors(BugTest.new)
  
  # Nice little instance counter for some feedback
  if (i % 1000) == 0
    puts i
  end
  i += 1
end

RealData.java

public class RealData
{
    // Works with any interface
    private Runnable errors;
    public void setErrors(Runnable errors)
    {
        this.errors = errors;
    }
}