# Initialization Order of Member Variables

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### Member Variable Initialization Order

> static variable declaration -> field variable declaration -> constructor block

* `static variable declaration`
  * Loaded into the `Method area`
  * Variables are initialized first when the class is loaded
* `field variable declaration`
  * Loaded into the `Heap area`
  * Initialized before the constructor block when the object is created
* `constructor block`
  * Loaded into the `Heap area`
  * When the object is created, the JVM internally locks; the visibility of final variables among field variables is initialized after the constructor block ends
  * If already initialized in the field variable declaration, those values are overwritten

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### Initialization Timing

* **`Class variables`**
  * Initialized only once when the class is first loaded
* **`Instance variables`**
  * Initialized for each instance whenever an instance is created

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### Initialization Order

* **`Class variables`**
  * Default value -> Explicit initialization -> Class initialization block
* **`Instance variables`**
  * Default value -> Explicit initialization -> Instance initialization block -> Constructor