import java.lang.reflect.Field;

class SomeClass {
    private int privateValue = 0;

    public int getPrivateValue() {
        return privateValue;
    }

    public void setPrivateValue(int privateValue) {
        this.privateValue = privateValue;
    }
}

public class Test {
    public static void main(String args[]) throws NoSuchFieldException, IllegalAccessException {
        SomeClass myClass = new SomeClass();

        // --- Method 1 ---
        // Using setter
        System.out.println(myClass.getPrivateValue());  // 0
        myClass.setPrivateValue(10);
        System.out.println(myClass.getPrivateValue());  // 10

        // --- Method 2 ---
        // Using java.lang.reflect tools
        System.out.println(myClass.getPrivateValue());  // 10
        Field privateValue = SomeClass.class.getDeclaredField("privateValue");
        privateValue.setAccessible(true);
        privateValue.set(myClass, 20);
        System.out.println(myClass.getPrivateValue());  // 20

    }
}