Use Array.setInt to fill an array : Array « Reflection « Java Tutorial

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import static java.lang.System.err;

import java.lang.reflect.Array;

public class ArrayTroubleAgain {
  public static void main(String... args) {
    Integer[] ary = new Integer[2];
    try {
      Array.setInt(ary, 0, 1); // IllegalArgumentException

      // production code should handle these exceptions more gracefully
    } catch (IllegalArgumentException x) {
      err.format("Unable to box%n");
    } catch (ArrayIndexOutOfBoundsException x) {
      x.printStackTrace();
    }
  }
}