public synchronized static void setSecurityManager(SecurityManager sm)
public static synchronized void setSecurityManager(SecurityManager sm)
  public synchronized static void setSecurityManager(SecurityManager sm)  {    // Implementation note: the field lives in Runtime because of bootstrap    // initialization issues. This method is synchronized so that no other    // thread changes it to null before this thread makes the change.    if (Runtime.securityManager != null)      Runtime.securityManager.checkPermission        (new RuntimePermission("setSecurityManager"));    Runtime.securityManager = sm;        }