Java How to access private static member of class

Question

Hi may I know how to access private static member outside Java classes?

I want to check if a value is set correctly.

"*I want to check if a value is set correctly.*" Don't use reflection, it breaks encapsulation. If you need to check the value, introduce a (possibly package-private) getter for the field. — Turing85, Sep 23 '20 at 19:42
You don't. If it's private it's not meant to be accessed. Or by providing a getter. — Federico klez Culloca, Sep 23 '20 at 19:43

Dmytro Mitin · Accepted Answer · 2020-09-24T20:26:04.340

(All necessary alerts about using reflection.)

Using reflection

import java.lang.reflect.Field;

public class Test {
    public static void main(String[] args) throws Exception {
//      Class<A> clazz = A.class;            // if you know the class statically i.e. at compile time
        Class<?> clazz = Class.forName("A"); // if you know class name dynamically i.e. at runtime
        Field field = clazz.getDeclaredField("x");
        field.setAccessible(true);
        System.out.println(field.getInt(null)); // 10
    }
}

class A {
    private static int x = 10;
}

null is because the field is static, so there is no need in an instance of A.

How to read the value of a private field from a different class in Java?

`field.setAccessible(true);` is a crucial bit for accessing private members, thanks @Dmytro — Nestor Milyaev, Oct 18 '22 at 15:41

score 1 · Answer 2 · answered Sep 23 '20 at 20:59

1

I've never used it, but I've heard that PowerMock is capable of testing private methods as well. https://github.com/powermock/powermock

answered Sep 23 '20 at 20:59

MrBrightside

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Java How to access private static member of class

2 Answers2