随笔分类 - Java
摘要：Volatile Since Java 5 the volatile keyword guarantees more than just the reading from and writing to main memory of variables. Actually, the volatile
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摘要：ArrayList vs LinkedList vs Vector From the hierarchy diagram, they all implement List interface. They are very similar to use. Their main difference i
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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
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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
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摘要：1. Final keyword Once a variable X is defined final, you can't change the reference of X to another object, after the initialization. But you can chan
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摘要：Reference: [1] https://www.mkyong.com/regular-expressions/how-to-validate-ip-address-with-regular-expression/ Description Whole combination means, dig
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摘要：References: [1]. http://www.javaworld.com/article/2074481/java-concurrency/java-101--understanding-java-threads--part-4 thread-groups--volatility--and
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摘要：1. Enum Class 2. Use Enum Class
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摘要：If a file has content like which are all key-value pairs, we could use properties.load() to parse it. The reason to use Thread.currentThread().getCont
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摘要：In a Maven project, we may often struggle to get a certain file (e.g. json file or sql file). Here is how to place the resource file and use it in the
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