Why is the wait() method always in the synchronized block?

Wait() is a meaningful method when the notify() method also exists. So it's always about interaction between threads, and you need synchronization to work. You may think that these processes should be implicit, but they are not helpful at all for the following reasons::

It's not always wait() in meaning. There is a condition to be satisfied, otherwise wait until it is satisfied. It's going to work like this.

if(!condition){
    wait();
}

However, if condition is set by multiple threads, synchronization is required for proper operation.

There are a few more things that are wrong because the thread stops waiting does not necessarily mean that condition is true:

What is needed to solve these cases is to modify the code below always:

synchronized(lock){
    while(!condition){
        lock.wait();
    }
}

It would be better to solve the concepts provided by the java.util.concurrent package without being bound by Synchronization.