## Why is this an issue?

Storing a value inside a collection at a given key or index and then unconditionally overwriting it without reading the initial value is a case of a "dead store".

    letters.put("a", "Apple");
    letters.put("a", "Boy");  // Noncompliant

    towns[i] = "London";
    towns[i] = "Chicago";  // Noncompliant

This practice is redundant and will cause confusion for the reader. More importantly, it is often an error and not what the developer intended to do.