SupercollideHashMap.java

import java.util.*;
import java.lang.*;

class Main {

	public static void main (String[] args) throws java.lang.Exception {
		int size = 65536;
		Map m;
		long starttime, endtime;

		m = new HashMap();
		starttime = System.currentTimeMillis();

		for (int i = 0; size > i; ++i) {
			m.put(new NObject(), true);
		}

		endtime = System.currentTimeMillis();

		System.out.printf("Inserting %d evil elements took %d ms\n", size, endtime - starttime);

		m = new HashMap();
		starttime = System.currentTimeMillis();

		for (int i = 0; size > i; ++i) {
			m.put(new Object(), true);
		}

		endtime = System.currentTimeMillis();

		System.out.printf("Inserting %d good elements took %d ms\n", size, endtime - starttime);
	}

	public static class NObject {
		@Override public int hashCode() { return 1; }
	}

}