<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">import java.util.List;

public class WildcardErrorBad {

    void swapFirst(List&lt;? extends Number&gt; l1, List&lt;? extends Number&gt; l2) {
      Number temp = l1.get(0);
      l1.set(0, l2.get(0)); // expected a CAP#1 extends Number,
                            // got a CAP#2 extends Number;
                            // same bound, but different types
      l2.set(0, temp);      // expected a CAP#1 extends Number,
                            // got a Number
    }
}
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