Investigations into transit bug: https://github.com/cognitect/transit-java/issues/20 http://dev.clojure.org/jira/browse/CLJS-1761 http://dev.clojure.org/jira/browse/CLJS-1759

ParallelStressTest.java

package mytransit;


import com.cognitect.transit.TransitFactory;
import com.cognitect.transit.WriteHandler;
import com.cognitect.transit.Writer;

import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;


public class ParallelStressTest {

    static Map<Class, WriteHandler<?, ?>> customHandlersSingleton = customHandlers();

    static Map<Class, WriteHandler<?, ?>> customHandlers() {
        HashMap<Class, WriteHandler<?, ?>> h = new HashMap<Class, WriteHandler<?, ?>>();
        h.put(String.class, customWriteHandler());
        return h;
    }

    static WriteHandler customWriteHandler() {
        return new WriteHandler() {
            @Override
            public String tag(Object o) {
                return "s";
            }

            @Override
            public Object rep(Object o) {
                return "OVERRIDDEN";
            }

            @Override
            public String stringRep(Object o) {
                return null;
            }

            @Override
            public WriteHandler getVerboseHandler() {
                return new WriteHandler() {
                    @Override
                    public String tag(Object o) {
                        return "s";
                    }

                    @Override
                    public Object rep(Object o) {
                        return "OVERRIDDEN";
                    }

                    @Override
                    public String stringRep(Object o) {
                        return null;
                    }

                    @Override
                    public WriteHandler getVerboseHandler() {
                        return null;
                    }
                };
            }
        };
    }

    static String write(String o, TransitFactory.Format format, Map<Class, WriteHandler<?, ?>> customHandlers) {
        try {
            OutputStream out = new ByteArrayOutputStream();
            Writer w = TransitFactory.writer(format, out, customHandlers);
            w.write(o);
            return out.toString();
        } catch (Throwable e) {
            throw new RuntimeException(e);
        }
    }

    public static void runParallel(Runnable r) {
        int n = Runtime.getRuntime().availableProcessors() * 2;
        ThreadGroup tg = new ThreadGroup("runParallel");
        for (int i = 0; i < n; i++) {
            new Thread(tg, r).start();
        }
    }

    public static void main(String[] args) {
        runParallel(new WriteTestManyHandlers());
    }

    static class WriteTestOneHandlers implements Runnable {
        public void run() {
            while (true) {
                String result;
                try {
                    result = write("0", TransitFactory.Format.JSON, customHandlersSingleton);
                } catch (RuntimeException e) {
                    System.out.println(e);
                    return;
                }
                try {
                    assert "\"OVERRIDDEN\"".equals(result);
                } catch (AssertionError e) {
                    System.out.println(e);
                    return;
                }
            }
        }
    }

    static class WriteTestManyHandlers implements Runnable {
        public void run() {
            public void run() {
                while (true) {
                    String result;
                    try {
                        result = write("0", TransitFactory.Format.JSON, customHandlers());
                    } catch (RuntimeException e) {
                        System.out.println(e);
                        return;
                    }
                    try {
                        assert "\"OVERRIDDEN\"".equals(result);
                    } catch (AssertionError e) {
                        System.out.println(e);
                        return;
                    }
                }
            }
        }
    }
}

Extra run is in WriteTestManyHandlers.