guava/src/com/google/common/collect/CompactHashMap.java
void insertEntry(int entryIndex, @Nullable K key, @Nullable V value, int hash) {
    this.entries[entryIndex] = ((long) hash << 32) | (NEXT_MASK & UNSET);
    this.keys[entryIndex] = key;
    this.values[entryIndex] = value;
  }
void insertEntry(int entryIndex, @Nullable K key, @Nullable V value, int hash) {
    this.entries[entryIndex] = ((long) hash << 32) | (NEXT_MASK & UNSET);
    this.keys[entryIndex] = key;
    this.values[entryIndex] = value;
  }
Creates a fresh entry with the specified object at the specified position in the entry arrays.