use Proc::ProcessTable;

my $processes = new Proc::ProcessTable;

my @java_processes =
  grep { $_->cmndline =~ /^\/System/ } @{ $processes->table }; # fake pattern, got no java at home ;-)

foreach my $java_process (@java_processes) {
    my $pid = $java_process->pid;
    # more stuff with this pid

    my $ppid = $java_process->ppid;
    my @parent = grep { $_->pid == $ppid } @{ $processes->table };
    # more stuff with the parent

    my $gppid = $parent[0]->ppid;
    my @gparent = grep { $_->pid == $gppid } @{ $processes->table };
    # more stuff with the grandparent

    my $ggppid = $gparent[0]->ppid;
    my @ggparent = grep { $_->pid == $ggppid } @{ $processes->table };
    # more stuff with the great-grandparent
    
}