You can do it using reflection, but unless there is a very good reason to do so, you should first reconsider your design.
The code below prints 123, even when called from outside A.
public static void main(String[] args) throws Exception {
Method m = A.class.getDeclaredMethod("getC");
m.setAccessible(true); //bypasses the private modifier
int i = (Integer) m.invoke(new A());
System.out.println("i = " + i); //prints 123
}
public static class A {
private int getC() {
return 123;
}
}