android/guava/src/com/google/common/collect/CompactHashSet.java
public void trimToSize() {
    if (needsAllocArrays()) {
      return;
    }
    int size = this.size;
    if (size < entries.length) {
      resizeEntries(size);
    }
    int minimumTableSize = Hashing.closedTableSize(size, LOAD_FACTOR);
    if (minimumTableSize < table.length) {
      resizeTable(minimumTableSize);
    }
  }
public void trimToSize() {
    if (needsAllocArrays()) {
      return;
    }
    int size = this.size;
    if (size < entries.length) {
      resizeEntries(size);
    }
    int minimumTableSize = Hashing.closedTableSize(size, LOAD_FACTOR);
    if (minimumTableSize < table.length) {
      resizeTable(minimumTableSize);
    }
  }
Ensures that this {@code CompactHashSet} has the smallest representation in memory, given its
current size.