java中final修饰符的使用方法

package objectStudy;

public class FinalInstanceVaribaleTest {
 final int var1 = 1;//定义final实例变量时指定初始值。
 final int var2;
 final int var3;
 
 //在非静态初始化块中为final实例变量指定初始值。
 {
 var2 = 2;
 }
 
 // 在构造方法中为final实例变量指定初始值。
 public FinalInstanceVaribaleTest() {
 this.var3 = 3;
 }
 
 public static void main(String[] args) {
 FinalInstanceVaribaleTest finalInstanceVaribaleTest = new FinalInstanceVaribaleTest();
 System.out.println(finalInstanceVaribaleTest.var1);
 System.out.println(finalInstanceVaribaleTest.var2);
 System.out.println(finalInstanceVaribaleTest.var3);
 }

}