1. 源码

/**
   A computation to be performed with privileges enabled.  The computation is
   performed by invoking {@code AccessController.doPrivileged} on the
   {@code PrivilegedAction} object.  This interface is used only for
 　 computations that do not throw checked exceptions; computations that
 　 throw checked exceptions must use {@code PrivilegedExceptionAction}
 　 instead.
 启用权限时执行的计算。通过在{@code PrivilegedAction}对象上调用
 {@code AccessController.doPrivileged}来执行计算。
 此接口仅用于不抛出已检查异常的计算;
 抛出已检查异常的计算必须使用{@code PrivilegedExceptionAction}。
 *
 * @see AccessController
 * @see AccessController#doPrivileged(PrivilegedAction)
 * @see PrivilegedExceptionAction
 */

public interface PrivilegedAction<T> {
    /**
     　 Performs the computation.  This method will be called by
     　　{@code AccessController.doPrivileged} after enabling privileges.

     执行计算。启用权限后，{@code AccessController.doPrivileged}将调用此方法。

     　 @return a class-dependent value that may represent the results of the
     　         computation. Each class that implements
               {@code PrivilegedAction}
               should document what (if anything) this value represents.
       @see AccessController#doPrivileged(PrivilegedAction)
       @see AccessController#doPrivileged(PrivilegedAction,
                                           AccessControlContext)
     */
    T run();
}