android/guava/src/com/google/common/collect/Maps.java
static String toStringImpl(Map<?, ?> map) {
    StringBuilder sb = Collections2.newStringBuilderForCollection(map.size()).append('{');
    boolean first = true;
    for (Entry<?, ?> entry : map.entrySet()) {
      if (!first) {
        sb.append(", ");
      }
      first = false;
      sb.append(entry.getKey()).append('=').append(entry.getValue());
    }
    return sb.append('}').toString();
  }
static String toStringImpl(Map<?, ?> map) {
    StringBuilder sb = Collections2.newStringBuilderForCollection(map.size()).append('{');
    boolean first = true;
    for (Entry<?, ?> entry : map.entrySet()) {
      if (!first) {
        sb.append(", ");
      }
      first = false;
      sb.append(entry.getKey()).append('=').append(entry.getValue());
    }
    return sb.append('}').toString();
  }
An implementation of {@link Map#toString}.