In core Java concurrency, which three of the following are methods declared by java.lang.Object (select exactly three)? notify() notifyAll() isInterrupted() synchronized() interrupt() wait(long msecs) sleep(long msecs) yield()

Introduction / Context:
Java’s concurrency model splits behavior between the foundational java.lang.Object class and the java.lang.Thread class. This question tests whether you can correctly identify which synchronization-related methods actually live on Object rather than Thread.

Given Data / Assumptions:

• A list of eight APIs mixes Object methods, Thread methods, keywords, and unrelated calls.
• We must choose exactly three that are declared in java.lang.Object.

Concept / Approach:
In Java, intrinsic locking (monitors) is tied to every object instance. Consequently, the coordination primitives that manipulate an object’s monitor are instance methods on Object: wait() (and its overloads), notify(), and notifyAll(). Thread-scheduling helpers such as sleep() and yield() are static methods on Thread. Interruption APIs (interrupt(), isInterrupted()) also belong to Thread. The token synchronized is a language keyword, not a method.

Step-by-Step Solution:

Verification / Alternative check:
Consulting the Object API confirms the presence of wait/notify/notifyAll. Thread API holds sleep, yield, interrupt, and isInterrupted.

Why Other Options Are Wrong:
They point to Thread methods or a language keyword and are not declared on Object.

Common Pitfalls:
Assuming all concurrency helpers live on Thread; in fact, monitor control is on Object.

Final Answer:
1, 2, 6