java static keyword usage

TestStatic.java

public class TestStatic {
    public static void main(String[] args) {
        Sample sample1 = new Sample();
        Sample sample2 = new Sample();
        Sample sample3 = new Sample();

        Sample.number1 = 2;
        Sample.method1();

        sample1.setNumber2(1);
        sample2.setNumber2(3);
        sample3.setNumber2(4);

        System.out.println("number1 : " + Sample.number1);

        System.out.println("sample 1 : " + sample1.getNumber1() + ", " + sample1);
        System.out.println("sample 2 : " + sample2.getNumber1() + ", " + sample2);
        System.out.println("sample 3 : " + sample3.getNumber1() + ", " + sample3);
    }
}


public class Sample {
    public static int number1 = -1;
    int number2 = -1;

    public void setNumber1(int n) {
        this.number1 = n;
    }

    public int getNumber1() {
        return number1;
    }

    public int getNumber2() {
        return number2;
    }

    public void setNumber2(int number2) {
        this.number2 = number2;
    }

    public static void method1() {
        System.out.println("I'm static method");
    }

    @Override
    public String toString() {
        return "Sample{" +
                "number2=" + number2 +
                '}';
    }
}

Sample.java, TestStatic.java 클래스를 각기 만들어 사용하세요.