Topic discussion

I come to about Concurrent Collections i.e ConcurrentHashMap today but i never heard about it in any book or mock exam .

so my question:-

Is Concurrent Collections topic of Ocpjp 6 exam?

No - not in OCPJP 6.

I found this new and confusing concept today i.e "private methods can be used from outside the class" using "java.lang.reflect.Method"

example code:-

import java.lang.reflect.Method;
class PM
{
private void privateMethod(){System.out.print("private");
}
}
class ACC
{
public static void main(String args[]) throws Exception
{
Method m=PM.class.getDeclaredMethod("privateMethod");
m.setAccessible(true);
m.invoke(new PM());
}
}

Output : private

// private method is used from outside of class

So my question :-

Is the above concept is in OCPJP 6 exam?

No - Java Reflection is not in the exam.