I have a Java class named "MyClass" with a private attribute, of type "AnotherClass". MyClass has a private constructor, and "AnotherClass" has public constructor. "AnotherClass" has also a private String field, "value", which is initialized in constructor. I want to access in "Main" class this String.
The first class:
public class MyClass {
private AnotherClass obj;
private MyClass() {
obj = new AnotherClass();
}
}
The second class:
public class AnotherClass {
private String value;
public AnotherClass() {
value = "You got the private value!";
}
}
The main class:
public class Main {
static String name;
static AnotherClass obj;
public static void main(String[] args) throws Exception {
Class myClass;
myClass = Class.forName("main.MyClass");
Constructor<MyClass>[] constructors = myClass
.getDeclaredConstructors();
for (Constructor c : constructors) {
if (c.getParameters().length == 0) {
c.setAccessible(true);
MyClass myCls= (MyClass) c.newInstance();
Field myObjField = myClass
.getDeclaredField("obj");
myObjField.setAccessible(true);
obj = (AnotherClass) myObjField.get(myCls);
// If "value" is public, the program prints "You got the private value!"
// So "obj" is returned correctly, via reflection
// name = obj.value;
// System.out.println(name);
// Now I want to get the field "value" of "obj"
Field myStringField = obj.getClass().getDeclaredField("value");
myStringField.setAccessible(true);
// This line throws an exception
name = (String) myStringField.get(obj.getClass());
System.out.println(name);
}
}
}
}
I expect to see in the console "You got the private value!", but the program throws an exception:
Exception in thread "main" java.lang.IllegalArgumentException: Can not set java.lang.String field main.AnotherClass.value to java.lang.Class
So, I want to retrieve the private field, "value", without modifying "MyClass" and "AnotherClass", and without calling the public constructor from AnotherClass directly in main() . I want to get the value from "obj".
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