== Why is this an issue? By contract, the method ``++Object.wait(...)++``, ``++Object.notify()++`` and ``++Object.notifyAll()++`` should be called by a thread that is the owner of the object's monitor. If this is not the case an ``++IllegalMonitorStateException++`` exception is thrown. This rule reinforces this constraint by making it mandatory to call one of these methods only inside a ``++synchronized++`` method or statement. === Noncompliant code example [source,java] ---- private void removeElement() { while (!suitableCondition()){ obj.wait(); } ... // Perform removal } ---- or [source,java] ---- private void removeElement() { while (!suitableCondition()){ wait(); } ... // Perform removal } ---- === Compliant solution [source,java] ---- private void removeElement() { synchronized(obj) { while (!suitableCondition()){ obj.wait(); } ... // Perform removal } } ---- or [source,java] ---- private synchronized void removeElement() { while (!suitableCondition()){ wait(); } ... // Perform removal } ---- ifdef::env-github,rspecator-view[] ''' == Implementation Specification (visible only on this page) === Message Make this call to "[wait(...)|notify()|notifyAll()]" only inside a synchronized block to be sure to hold the monitor on "[this|xxx]" object. endif::env-github,rspecator-view[]