final變量的初始化

public class TestDemo {
	//初始化方式一，在定義變量時直接賦值
	private final int x1=1;
	
	//初始化方式二,聲明完變量後在構造方法中爲其賦值
	private final int x2;
	public TestDemo(){
		x2=2;
	}
	
	//初始化方式三，聲明完變量後在初始化代碼塊爲其賦值
	final int x3;
	{
		x3=3;
	}
	//若爲靜態變量，則在靜態代碼塊中爲其賦值
	final static int x4;
	static{
		x4=4;
	}
	
}