Id.java

/*======================================================================*\
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\*======================================================================*/

import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.List;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

class Id {
    static final ConcurrentSkipListSet<Integer> _all_ids = new ConcurrentSkipListSet<>();
    
    public Id(final int id) {
        this._my_id = id;
        boolean inserted =  _all_ids.add(id);
        assert inserted;
        new WeakReference<>(this, theseIDs).enqueue();
    }

    public void cleanUp() {
        if (! this._cleaned) {
            _all_ids.remove(this._my_id);
            _cleaned = true;
        }
    }

    static ReferenceQueue<Id> theseIDs = new ReferenceQueue<Id>();
    static {
        Thread t = new Thread(() ->  {
            while (true) {
                try {
                    Id id = theseIDs.remove().get();
                    if (id != null) {
                        id.cleanUp();
                    }
                } catch (InterruptedException ie) {
                    // intrruptions are so rude!
                }
            }
        });
        t.setDaemon(true);
        t.start();
    }

    private int _my_id;
    private boolean _cleaned = false;
    
    
    public static void main(String... args) {
        List<WeakReference<Id>> weakIDs = IntStream.range(0, 5_000)
                .mapToObj(Id::new)
//                .peek(id -> { int[] i =  new int[5000];})
//                .peek(id -> {
//                    assert !id._cleaned;
//                    System.out.println(_all_ids.size());
//                })
                .map(id -> new WeakReference<>(id))
                .collect(Collectors.toList());

        // simulate long running app
        System.gc();
        System.gc();
        
        // likely all weak references collected, expect zero
        System.out.println(_all_ids.size());
    }
}

Meaning those two options are mutually exclusive?

The header in the gist lacks a e-mail adders to send this info to. A google search of this gist goes to a bunch of job boards and some freelance sites I haven't made accounts for, but no e-mail as per the instructions.

Is this an UntraCoin project or a bitcoin project?

ping me at danno.ferrin@shemnon.com