Java – synchronization block within synchronization block

Can I include a synchronization block in another object to synchronize another object?

Example:

synchronized(myObjetc1){
    // code
    synchronized(myObjetc2){
        // code         
    }           
}

If so, is it still the right technology or is it too risky?

Solution

If you synchronize in the same order elsewhere, it's no problem

If some other threads want to execute the following code

synchronized(myObjetc2){
    // code
    synchronized(myObjetc1){
        // code         
    }           
}

You may encounter an impasse

Assuming that the above variables refer to the same object, consider the following The first thread (your code) locks the monitor on myobjetc1 Thread scheduler switches thread context The second thread (code above) locks the monitor on myobjetc2 Thread scheduler switches thread context The first thread attempts to lock the monitor on myobjetc2 It must wait because the second thread has it Thread scheduler switches context The second thread attempts to lock the monitor on myobjetc1 It must wait because the first thread has it boom! Deadlock