This instance method synchronizes on this.getClass(). If this class is subclassed, subclasses will synchronize on the class object for the subclass, which isn't likely what was intended. For example, consider this code from java.awt.Label:

     private static final String base = "label";
     private static int nameCounter = 0;
     String constructComponentName() {
        synchronized (getClass()) {
            return base + nameCounter++;
        }
     }
     

Subclasses of Label won't synchronize on the same subclass, giving rise to a datarace. Instead, this code should be synchronizing on Label.class

     private static final String base = "label";
     private static int nameCounter = 0;
     String constructComponentName() {
        synchronized (Label.class) {
            return base + nameCounter++;
        }
     }
     

Bug pattern contributed by Jason Mehrens