reflect permission and security manage in java

import java.lang.reflect.Field;
import java.lang.reflect.ReflectPermission;

public class ReflectField {

private String test = "test string in class ReflectField!";

public static void main(String[] args) throws Exception {
Class ref = ReflectField.class;

SecurityManager nsm = new SecurityManager();
System.setSecurityManager(nsm);
ReflectPermission rp = new ReflectPermission("suppressAccessChecks", null);
System.out.println(rp);
// java.security.AccessControlException:
// access denied (java.lang.reflect.ReflectPermission suppressAccessChecks
// nsm.checkPermission(rp);
SecurityManager sm = System.getSecurityManager();
System.out.println(sm);

Field[] fields = ref.getDeclaredFields();
System.out.println(fields.length);
for (Field field : fields) {
// java.security.AccessControlException:
// access denied (java.lang.reflect.ReflectPermission suppressAccessChecks
// field.setAccessible(true);

// java.lang.IllegalArgumentException
// at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java)
// System.out.println(field.get(ref));

System.out.println(field.getName());
}

}

}

This main method had set a security manage to this java application, in order to prevent java reflect get and set private fields.

Apache2.2.4中无法建立虚拟路径的问题

在Apache2中可以用Alias VirtualPath SystemPath 来虚拟目录，可以指定到DocumentRoot之外的系统目录中。
在Apache2 默认一般是支持Alias的，所以在配置文件里用Alias /test /var/test这样来访问/var/test/目录下的文件。但在设置时发现Alias设置了之后无效，总是报You don't have permission to access /test/ on this server.这样的错误，因为语法很简单，肯定不会错，而且httpd -M也看到alias module被加载进来了，却还是不行，即使对应的/var/test目录设置为755或者是777都无法访问，所以是配置文件其他设置出问题了。
修改几个参数后发现

# Each directory to which Apache has access can be configured with respect
# to which services and features are allowed and/or disabled in that
# directory (and its subdirectories).
#
# First, we configure the "default" to be a very restrictive set of
# features.
#
<Directory />
    Options FollowSymLinks
    AllowOverride None
    Order deny,allow
    Deny from all
</Directory>

这里设置了Deny from all导致了Alias无效，改成Allow或者注掉此行即可。