/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
 
int[] spam = new int[] { 1, 2, 3,1 };
containsDuplicate(spam);
 
System.out.println( new HashSet<>( ) ) ;
 
	}
	  public static boolean containsDuplicate(int[] nums) {
        System.out.println((Arrays.asList(nums)).size());
        return new HashSet<>(Arrays.asList(nums)).size() !=nums.length;
 
    }
}

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