-XX:PermSize and MaxPermSize

Discussion in 'Java' started by ninjazombiee@gmail.com, Oct 3, 2008.

  1. Guest

    Hi all,

    what do these parameters mean - PermSize ans MaxPermSize and how do
    they relate to -Xmx (maximum heap size of JVM)?

    Thanks.
     
    , Oct 3, 2008
    #1
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  2. Lew Guest

    On Oct 3, 10:35 am, wrote:
    > what do these parameters mean - PermSize ans MaxPermSize and how do
    > they relate to -Xmx (maximum heap size of JVM)?


    <http://java.sun.com/javase/technologies/hotspot/vmoptions.jsp>

    --
    Lew
     
    Lew, Oct 3, 2008
    #2
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  3. Dave Miller Guest

    wrote:
    > Hi all,
    >
    > what do these parameters mean - PermSize ans MaxPermSize and how do
    > they relate to -Xmx (maximum heap size of JVM)?
    >
    > Thanks.

    Permanent generation (MaxPermSize setting) is separate heap space that
    is not garbage collected (ergo the permanent). Whatever is allocated to
    perm is in addition to the heap set with -Xmx.



    --
    Dave Miller
    Java Web Hosting
    http://www.cheap-jsp-hosting.com/
     
    Dave Miller, Oct 3, 2008
    #3
  4. Guest

    On Oct 3, 10:19 pm, Dave Miller <> wrote:
    > wrote:
    > > Hi all,

    >
    > > what do these parameters mean - PermSize ans MaxPermSize and how do
    > > they relate to -Xmx (maximum heap size of JVM)?

    >
    > > Thanks.

    >
    > Permanent generation (MaxPermSize setting) is separate heap space that
    > is not garbage collected (ergo the permanent). Whatever is allocated to
    > perm is in addition to the heap set with -Xmx.
    >
    > --
    > Dave Miller
    > Java Web Hostinghttp://www.cheap-jsp-hosting.com/


    Thanks,

    do you think that a insufficiency in that Perm space could also cause
    java.lang.OutOfMemoryException?
     
    , Oct 5, 2008
    #4
  5. Guest

    On Oct 3, 10:19 pm, Dave Miller <> wrote:
    > wrote:
    > > Hi all,

    >
    > > what do these parameters mean - PermSize ans MaxPermSize and how do
    > > they relate to -Xmx (maximum heap size of JVM)?

    >
    > > Thanks.

    >
    > Permanent generation (MaxPermSize setting) is separate heap space that
    > is not garbage collected (ergo the permanent). Whatever is allocated to
    > perm is in addition to the heap set with -Xmx.
    >
    > --
    > Dave Miller
    > Java Web Hostinghttp://www.cheap-jsp-hosting.com/


    Is it possible that the wrong setting of PermSize could also cause
    java.lang.OutOfMEmoryException?

    Thanks!
     
    , Oct 5, 2008
    #5
  6. Jim Guest

    On Sun, 5 Oct 2008 07:53:42 -0700 (PDT), wrote:

    >On Oct 3, 10:19 pm, Dave Miller <> wrote:
    >> wrote:
    >> > Hi all,

    >>
    >> > what do these parameters mean - PermSize ans MaxPermSize and how do
    >> > they relate to -Xmx (maximum heap size of JVM)?

    >>
    >> > Thanks.

    >>
    >> Permanent generation (MaxPermSize setting) is separate heap space that
    >> is not garbage collected (ergo the permanent). Whatever is allocated to
    >> perm is in addition to the heap set with -Xmx.
    >>
    >> --
    >> Dave Miller
    >> Java Web Hostinghttp://www.cheap-jsp-hosting.com/

    >
    >Is it possible that the wrong setting of PermSize could also cause
    >java.lang.OutOfMEmoryException?
    >
    >Thanks!


    Yes, if so go higher, especially if you have quite a few
    projects open in the workspace.

    Many times you'll get a popup indicating that PermGen was the reason,
    sometimes not. Save early, save often!

    Jim
     
    Jim, Oct 5, 2008
    #6
  7. Dave Miller Guest

    wrote:
    > On Oct 3, 10:19 pm, Dave Miller <> wrote:
    >> wrote:
    >>> Hi all,
    >>> what do these parameters mean - PermSize ans MaxPermSize and how do
    >>> they relate to -Xmx (maximum heap size of JVM)?
    >>> Thanks.

    >> Permanent generation (MaxPermSize setting) is separate heap space that
    >> is not garbage collected (ergo the permanent). Whatever is allocated to
    >> perm is in addition to the heap set with -Xmx.
    >>
    >> --
    >> Dave Miller
    >> Java Web Hostinghttp://www.cheap-jsp-hosting.com/

    >
    > Thanks,
    >
    > do you think that a insufficiency in that Perm space could also cause
    > java.lang.OutOfMemoryException?

    Yes, but it should indicate PermGen meaning that the system tried to
    move something into the perm heap and there was no room. If you are
    getting a garden variety OOM message it's more likely in the main heap.

    It's pretty easy to test, set one way down and the other way up and see
    what happens.

    --
    Dave Miller
    Java Web Hosting
    http://www.cheap-jsp-hosting.com/
     
    Dave Miller, Oct 6, 2008
    #7
  8. mesas123

    Joined:
    Jan 12, 2011
    Messages:
    2
    local references to Thread

    I haven't seen the dreaded PermGen (knock on wood) since I took care to null any local reference to a Thread, though it seems ridiculous:

    public void method {
    Thread dt= new MyThreadClass();
    dt.start();
    ...
    dt=null;

    }

    Is it possible there's a bug in the GC.
     
    mesas123, Jan 12, 2011
    #8
  9. mesas123

    Joined:
    Jan 12, 2011
    Messages:
    2
    local references to Thread

    I haven't seen the dreaded PermGen (knock on wood) since I took care to null any local reference to a Thread, though it seems ridiculous:

    public void method {
    Thread dt= new MyThreadClass();
    dt.start();
    dt=null; // before you leave

    }

    Is it possible there's a bug in the GC?
     
    mesas123, Jan 12, 2011
    #9
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