java array check duplicates

public class DuplicateArrayElement {
  public static void main(String[] args) {
    int[] numArray = {2, 6, 7, 6, 2, 19, 1, 19};
    for(int i = 0; i < numArray.length; i++){
      for(int j = i + 1; j < numArray.length; j++){
        if(numArray[i] == numArray[j]){
          System.out.println("Duplicate element found " + numArray[j]);
        }
      }
    }    
  }
}

duplicates = false;

for(i = 0; i < zipcodeList.length; i++) {
	for(j = i + 1; k < zipcodeList.length; j++) {
  		if(j != i && zipcodeList[j] == zipcodeList[i]) {
   	  		duplicates = true;
		}
	}
}

import java.util.*;
public class DuplicateClass {

    public static void main(String[] args) {
        int[] values = { 7, 2, 6, 1, 4, 7, 4, 5, 4, 7, 7, 3, 1 };
        duplicate(values);
    }

    public static void duplicate(int numbers[]) {
        Arrays.sort(numbers);
        int previous = numbers[0] - 1;
        
        int dupCount = 0;

        for (int i = 0; i < numbers.length; ++i) {
            if (numbers[i] == previous) {
                ++dupCount;
            } else {
                previous = numbers[i];
            }
        }
        System.out.println("There were " + dupCount + " duplicates in the array.");
    }
}

// Uses a set, which does not allow duplicates 

for (String name : names) 
{
     if (set.add(name) == false) 
     {
        // print name your duplicate element
     }
}