public Object get(int key) {

    Entry[] table = this.table;
    int bucket = Math.abs(key) % table.length;
    for (Entry e = table[bucket]; e != null; e = e.next) {
      if (e.key == key) {
        return e.value;
      }
    }

    return null;
  }
Returns the object to which the given key is mapped. If no object is mapped to the given key,
<code>null</code> is returned.

@throws IllegalArgumentException <code>key</code> is less than zero
geode-core/src/main/java/org/apache/geode/internal/admin/ListenerIdMap.java