每天更强一点...

摘要： find . -name "*.java" -type f find all the files within a director and its sub-directory ended with .java rm *~ delete all the files ended with ~ grep 阅读全文

摘要： HashMap 是线程不安全的，主要对于写操作来说，两个以上线程同时写入Map会被互相覆盖。线程安全指的保证对同一个map的写入操作按照顺序进行，一次只能一个线程更改。比如向HashMap里put(key, value1)有可能key对应的是其他线程同时写入的value2 HashMap的遍历有两种 阅读全文

摘要： Better to use a circuit breaker which supports the following set of features: Automatically time-out calls that take longer than a defined threshold. 阅读全文

摘要： 1. Cassandra is quicker than postgre and have lower change to lose data. Cassandra doesn't have foreign keys, locking mechanism and etcs, so that it's 阅读全文

摘要： 1. Bubble Sort Performance Worst case performance O(n^2)Best case performance O(n)Average case performance O(n^2)Worst case space complexity O(1) auxi 阅读全文

摘要： 1. Merge Sort PerformanceWorst case performance O(n log n)Best case performance O(n log n) typical, O(n) natural variantAverage case performance O(n l 阅读全文

摘要： 1. cat <<EOF 2. let i++reference:[1] http://askubuntu.com/questions/385528/how-to-increment-a-variable-in-bash The same as: or even 3. getopts 阅读全文

摘要： 一) 分布式Java应用 1.1 基于消息方式实现系统间的通信 数据传输 TCP/IP　可靠的网络传输协议，首先给通信双方建立链接之后再进行数据传输，保证链接及数据传输的可靠，因此会牺牲一些性能 UDP/IP　不保证数据一定到达的网络传输协议，并不直接给通信的双方建立链接而是发送到网络上进行传递。性 阅读全文

摘要： References: [1] http://dev.bizo.com/2013/04/sensible-defaults-for-apache-httpclient.html We have hit an issue recently that the httpClient is too slow 阅读全文

摘要： 1. Install Xvfbm, google-chrome-stable and chromedriver in Jenkins sudo apt-get install -y xvfb google-chrome-stable Down chromedriver from https://si 阅读全文