HashMap和垃圾收集：我需要的变量重新赋值之前调用clear（）？ [英] HashMap and garbage collection: do I need to call clear() before variable re-assignment?

问题描述

也许这是一个愚蠢的问题，但我不知道的垃圾收集过程。

Maybe it's a silly question but I'm not sure about the garbage collection process.

考虑这个code：

private HashMap<String, Parameter> configuration = new HashMap<String, Parameter>();

...
//add some items to configuration
...

//now get another configuration
HashMap<String, Parameter> parameters = new HashMap<String, Parameter>();
for (String parameterName : configurationParameterNameList) {
    parameters.put(parameterName, reader.readParameter(parameterName));
}

//and reassign the variable
this.configuration.clear();
this.configuration = parameters;

我需要调用 configuration.clear（）之前重新分配呢？ 参数类只包含几个字符串变量中。

Do I need to call configuration.clear() before reassign it? Parameter class contains only a few String variables inside.

推荐答案

没有，你并不需要调用清（）。

No, you don't need to call clear().

只要不出意外有一个参考的HashMap 它（及其所有条目）将尽快更改符合垃圾收集 this.configuration 为其他值。

As long as nothing else has a reference to that HashMap it (and all of its entries) will become eligible for garbage collection as soon as you change this.configuration to another value.

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