“同步”是什么意思？ - What does 'synchronized' mean?

问题：

I have some questions regarding the usage and significance of the synchronized keyword. 我对synchronized关键字的用法和重要性有一些疑问。

• What is the significance of the synchronized keyword? synchronized关键字的意义是什么？
• When should methods be synchronized ? 方法应什么时候synchronized ？
• What does it mean programmatically and logically? 从程序上和逻辑上是什么意思？

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解决方案：

参考一： https://stackoom.com/question/4YRR/同步-是什么意思
参考二： https://oldbug.net/q/4YRR/What-does-synchronized-mean