'synchronized' method

Reports the synchronized modifier on methods.

There are several reasons a synchronized modifier on a method may be a bad idea:

As little work as possible should be performed under a lock. Therefore it is often better to use a synchronized block and keep there only the code that works with shared state.
Synchronization becomes a part of a method's interface. This makes a transition to a different locking mechanism difficult.
Keeping track of what is locking a particular object gets harder.
The DoS (denial-of-service) attack becomes feasible either on purpose or unknowingly when inheriting the method's class.

As an alternative, consider synchronizing on a private final lock object, access to which can be completely controlled.

A quick-fix is provided to wrap the method body with synchronized(this).

Example:

class Main {
  public synchronized void fooBar() {
  }
}

After the quick-fix is applied:

class Main {
  public void fooBar() {
    synchronized (this) {
    }
  }
}

You can configure the following options for this inspection:

Include native methods - include native methods into the inspection's scope.
Ignore methods overriding a synchronized method - do not report methods that override a synchronized method.

Inspection options

Option	Type	Default
Include native methods	Checkbox	true
Ignore methods overriding a synchronized method	Checkbox	true

Inspection Details
Available in:	IntelliJ IDEA 2023.3, Qodana for JVM 2023.3
Plugin:	Java, 233.SNAPSHOT

Last modified: 13 July 2023