No subject

interesting for the developers working on gvSIG code to
review the Sun documentation about thread synchronization [1]. A bad use
of threads can affect the execution and
performance of the code.

This can affect a code so simple like delaying the creation of an object
until the moment is required instead of
creating it when the containing object is built. For example:

class Example {
  Service service = null;

  public String getService() {
    if( this.service == null ) {
      this.seobjetorvice = new Service();
    }
    return this.service;
  }
}

This construction on a multithreaded environment can cause the creation
of two instances of Service, once for every thread.

This can be resolved synchronizing the method:

class Example {
  Service service = null;

  public synchronized String getService() {
    if( this.service == null ) {
      this.service = new Service();
    }
    return this.service;
  }
}


Like this simple example, there are more cases where this situation can
happen, and not always the solution is
synchronizing the method. So we think the Sun tutorial is a worth
reading [1].


[1]http://java.sun.com/docs/books/tutorial/essential/concurrency/sync.html
[2]

-- 
--------------------------------------
Joaquin del Cerro Murciano
Responsable de producción de gvSIG
www.gvsig.org