import java.util.HashSet;
import java.util.Arrays;
import java.util.Date;

public class ArraysHashcodeIssue {

	public static void main(String[] args) {
		HashSet<Integer> hs = new HashSet<>(100000000,(float) 1.0); 
		long collide = 0; 
		long totalLoops = 0; 
		byte[] ba = new byte[4]; 
		System.gc(); 
		int hash=1; 
		long time = System.currentTimeMillis(); 
		for(byte d=0; d<15; d++) { 
			ba[0] = d; 
			for(byte i=-128; i<127; i++) { 
				ba[1] = i; 
				for(byte k=-128; k<127; k++) { 
					ba[2] = k; 
					for(byte j=-128; j<127; j++) { 
						ba[3] = j; 
						hash = Arrays.hashCode(ba); 
						if(hs.contains(hash)) { 
							collide++; 
						} else { 
							hs.add(hash); 
						} 
						totalLoops++; 
					} 
				} 
			} 
			
		} 
		System.out.println("total time =" + (System.currentTimeMillis() - time)); 
		System.out.println("collisions=" + collide + " loops=" + totalLoops); 

		System.exit(0); 

	}

}