The for-each loop is essentially read-only : For Each Loop « Statement Control « Java Tutorial

1. Java Tutorial
2. Statement Control
3. For Each Loop

public class MainClass {
  public static void main(String args[]) {
    int nums[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
 
    for(int x : nums) {
      System.out.print(x + " "); 
      x = x * 10; // no effect on nums
    }
   
    System.out.println();

    for(int x : nums) 
      System.out.print(x + " "); 

    System.out.println();
  }  
}

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1 2 3 4 5 6 7 8 9 10