Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #22728

Re: synchronized methods "under the hood"

Show all headers | View raw

bob smith schrieb:
> How do synchronized methods work "under the hood"?
>
> Is there some kind of byte associated with each object that acts as a semaphore?
>
> Thanks.
>

If I remember well the synchronized keyword is mapped to two things:

- In reflection it is mapped to the SYNCHRONIZED modifier:
 
http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/reflect/Modifier.html#SYNCHRONIZED

- In execution the invocation and return instruction is combined
   with a monitor enter and monitor exit.
 
http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-2.html#jvms-2.11.10

- For static methods the monitor is the class object, for non static
   methods the monitor is the instance object.
   http://docs.oracle.com/javase/specs/jls/se7/html/jls-8.html#jls-8.4.3.6

Bye

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

synchronized methods "under the hood" bob smith <bob@coolfone.comze.com> - 2013-03-05 09:02 -0800
  Re: synchronized methods "under the hood" Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-03-05 09:15 -0800
  Re: synchronized methods "under the hood" Jan Burse <janburse@fastmail.fm> - 2013-03-05 18:59 +0100
    Re: synchronized methods "under the hood" Jan Burse <janburse@fastmail.fm> - 2013-03-05 19:16 +0100
    Re: synchronized methods "under the hood" Jan Burse <janburse@fastmail.fm> - 2013-03-06 15:24 +0100
  Re: synchronized methods "under the hood" Roedy Green <see_website@mindprod.com.invalid> - 2013-03-05 12:19 -0800
    Re: synchronized methods "under the hood" Sven Köhler <remove-sven.koehler@gmail.com> - 2013-03-05 23:44 +0100
      Re: synchronized methods "under the hood" Roedy Green <see_website@mindprod.com.invalid> - 2013-03-06 04:28 -0800
        Re: synchronized methods "under the hood" Jan Burse <janburse@fastmail.fm> - 2013-03-06 15:20 +0100

csiph-web