Java_memo.md

Data Structures

You can find common data structures under package java.util and its sub-packages.

All of these classes compose the Java Collections Framework

Memo

ArrayList vs. Vector

• ArrayList is non-thread-safe
• Vector is thread-safe
• You can also get a thread-safe version of ArrayList via Collections.synchronizedList(List)

Bag or multiset

• according to Collection's doc in JDK: Bags or multisets (unordered collections that may contain duplicate elements) should implement this interface directly.
• 【todo】What's a bag?
  • Chapter 8: Bags and Sets
  • Multiset
• implementation references:
  • Bag.java from Algorithms, 4th Edition
  • Bag.java from apache common-collections, all bag implementations reside in package org.apache.commons.collection4.bag

【todo】

• ArrayDeque
  • an application - as queue storing request calls in okhttp - okhttp3.Dispatcher

data structures dedicated for android

• ArrayMap/SimpleArrayMap/ArraySet
• LruCache
• SparseArray/LongSparseArray/SparseXXXArray
• Pair