为什么这个代码没有给我相同的结果?静态和静态{}的情况

我有一个问题,在静态与{}和静态没有{}有什么区别。如果有人向我解释这两个代码之间的区别,我就会理解:为什么第一个代码会给我一个编译时错误?以及如何将static关键字与{}一起使用。

请查看我的第一个代码,其中有编译时错误:

public class Lambdas {

@FunctionalInterface
public interface Calculate {
    int calc(int x, int y);

}

static {

    Calculate add = (a, b) -> a + b;
    Calculate difference = (a, b) -> Math.abs(a-b);
    Calculate divide = (a,b) -> b!=0 ? a/b : 0;
    Calculate multiply = (c, d) -> c * d ;

}

public static void main(String[] args) {

    System.out.println(add.calc(3,2)); // Cannot resole symbol 'add'
    System.out.println(difference.calc(5,10));  // Cannot resole symbol 'difference'
    System.out.println(divide.calc(5, 0));  // Cannot resole symbol 'divide'
    System.out.println(multiply.calc(3, 5));  // Cannot resole symbol 'multiply'

}


}

第二个代码段工作正常:

public class Lambdas {

@FunctionalInterface
public interface Calculate {
    int calc(int x, int y);

}


static Calculate add = (a, b) -> a + b;
static Calculate difference = (a, b) -> Math.abs(a - b);
static Calculate divide = (a, b) -> b != 0 ? a / b : 0;
static Calculate multiply = (c, d) -> c * d;


public static void main(String[] args) {

    System.out.println(add.calc(3, 2)); 
    System.out.println(difference.calc(5, 10)); 
    System.out.println(divide.calc(5, 0));  
    System.out.println(multiply.calc(3, 5));  
}


}