java_concurrency2.java

private Long myNtfSeqNbrCounter = new Long(0);
private Long getNotificationSequenceNumber() {
     Long result = null;
     synchronized(myNtfSeqNbrCounter) {
         result = new Long(myNtfSeqNbrCounter.longValue() + 1);
         
         // ...
         
         myNtfSeqNbrCounter = new Long(result.longValue());
         
         // ...
         
         return result;
     }
}











//////////////////////////////////////////////////////









private Long myNtfSeqNbrCounter = new Long(0);
private Long getNotificationSequenceNumber() {
     Long result = null;
     synchronized(this) {
         result = new Long(myNtfSeqNbrCounter.longValue() + 1);
         
         // ...
         
         myNtfSeqNbrCounter = new Long(result.longValue());
         
         // ...
         
         return result;
     }
}










//////////////////////////////////////////////////////









private String myNtfSeqNbrLock = "lock";
private Long myNtfSeqNbrCounter = new Long(0);
private Long getNotificationSequenceNumber() {
     Long result = null;
     synchronized(myNtfSeqNbrLock) {
         result = new Long(myNtfSeqNbrCounter.longValue() + 1);
         
         // ...
         
         myNtfSeqNbrCounter = new Long(result.longValue());
         
         // ...
         
         return result;
     }
}











//////////////////////////////////////////////////////









private Object myNtfSeqNbrLock = new Object();
private Long myNtfSeqNbrCounter = new Long(0);
private Long getNotificationSequenceNumber() {
     Long result = null;
     synchronized(myNtfSeqNbrLock) {
         result = new Long(myNtfSeqNbrCounter.longValue() + 1);
         
         // ...
         
         myNtfSeqNbrCounter = new Long(result.longValue());
         
         // ...
         
         return result;
     }
}