An unreachable object may become reachable again. This can happen when the object’s finalize() method is invoked and the object performs an operation which causes it to become accessible to reachable objects.

No, in Java, once an object becomes unreachable, it cannot become reachable again. An object becomes unreachable when there are no references to it from any live threads or when all references to it have been explicitly set to null. The garbage collector in Java is responsible for reclaiming memory occupied by unreachable objects.

Once an object is unreachable, the garbage collector may eventually identify it during its execution and reclaim the memory occupied by that object. However, the object itself cannot become reachable again through any direct mechanism in the Java language.

In summary, once an object is unreachable, it is subject to garbage collection, and there is no mechanism to make it reachable again within the normal flow of Java programming.