Policy (Java SE 17 & JDK 17)
Description: declaration: module: java.base, package: java.security, class: Policy
Keywords: java.security.Policy class

Module java.base
Package java.security

# Class Policy

java.lang.Object
java.security.Policy

@Deprecated(since="17", forRemoval=true) public abstract class Policy extends Object
Deprecated, for removal: This API element is subject to removal in a future version.
This class is only useful in conjunction with the Security Manager, which is deprecated and subject to removal in a future release. Consequently, this class is also deprecated and subject to removal. There is no replacement for the Security Manager or this class.
A Policy object is responsible for determining whether code executing in the Java runtime environment has permission to perform a security-sensitive operation.

There is only one Policy object installed in the runtime at any given time. A Policy object can be installed by calling the `setPolicy` method. The installed Policy object can be obtained by calling the `getPolicy` method.

If no Policy object has been installed in the runtime, a call to `getPolicy` installs an instance of the default Policy implementation (a default subclass implementation of this abstract class). The default Policy implementation can be changed by setting the value of the `policy.provider` security property to the fully qualified name of the desired Policy subclass implementation. The system class loader is used to load this class.

Application code can directly subclass Policy to provide a custom implementation. In addition, an instance of a Policy object can be constructed by invoking one of the `getInstance` factory methods with a standard type. The default policy type is "JavaPolicy".

Once a Policy instance has been installed (either by default, or by calling `setPolicy`), the Java runtime invokes its `implies` method when it needs to determine whether executing code (encapsulated in a ProtectionDomain) can perform SecurityManager-protected operations. How a Policy object retrieves its policy data is up to the Policy implementation itself. The policy data may be stored, for example, in a flat ASCII file, in a serialized binary file of the Policy class, or in a database.

The `refresh` method causes the policy object to refresh/reload its data. This operation is implementation-dependent. For example, if the policy object stores its data in configuration files, calling `refresh` will cause it to re-read the configuration policy files. If a refresh operation is not supported, this method does nothing. Note that refreshed policy may not have an effect on classes in a particular ProtectionDomain. This is dependent on the Policy provider's implementation of the `implies` method and its PermissionCollection caching strategy.

Since:
  1.2
See Also:
  - `Provider`
  - `ProtectionDomain`
  - `Permission`
  - `security properties`

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static interface`
  `Policy.Parameters`
  Deprecated, for removal: This API element is subject to removal in a future version.
  This class is only useful in conjunction with the Security Manager, which is deprecated and subject to removal in a future release.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final PermissionCollection`
  `UNSUPPORTED_EMPTY_COLLECTION`
  Deprecated, for removal: This API element is subject to removal in a future version.
  A read-only empty PermissionCollection instance.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Policy()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Constructor for subclasses to call.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static Policy`
  `getInstance(String type, Policy.Parameters params)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Returns a Policy object of the specified type.
  `static Policy`
  `getInstance(String type, Policy.Parameters params, String provider)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Returns a Policy object of the specified type.
  `static Policy`
  `getInstance(String type, Policy.Parameters params, Provider provider)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Returns a Policy object of the specified type.
  `Policy.Parameters`
  `getParameters()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Return Policy parameters.
  `PermissionCollection`
  `getPermissions(CodeSource codesource)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Return a PermissionCollection object containing the set of permissions granted to the specified CodeSource.
  `PermissionCollection`
  `getPermissions(ProtectionDomain domain)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Return a PermissionCollection object containing the set of permissions granted to the specified ProtectionDomain.
  `static Policy`
  `getPolicy()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Returns the installed Policy object.
  `Provider`
  `getProvider()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Return the Provider of this Policy.
  `String`
  `getType()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Return the type of this Policy.
  `boolean`
  `implies(ProtectionDomain domain, Permission permission)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Evaluates the global policy for the permissions granted to the ProtectionDomain and tests whether the permission is granted.
  `void`
  `refresh()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Refreshes/reloads the policy configuration.
  `static void`
  `setPolicy(Policy p)`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Sets the system-wide Policy object.

  ### Methods declared in class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Field Details

  - ### UNSUPPORTED_EMPTY_COLLECTION

    public static final PermissionCollection UNSUPPORTED_EMPTY_COLLECTION
    Deprecated, for removal: This API element is subject to removal in a future version.
    A read-only empty PermissionCollection instance.
    Since:
      1.6

- ## Constructor Details

  - ### Policy

    public Policy()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Constructor for subclasses to call.

- ## Method Details

  - ### getPolicy

    public static Policy getPolicy()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Returns the installed Policy object. This value should not be cached, as it may be changed by a call to `setPolicy`. This method first calls `SecurityManager.checkPermission` with a `SecurityPermission("getPolicy")` permission to ensure it's ok to get the Policy object.
    Returns:
      the installed Policy.
    Throws:
      `SecurityException` - if a security manager exists and its `checkPermission` method doesn't allow getting the Policy object.
    See Also:
      - `SecurityManager.checkPermission(Permission)`
      - `setPolicy(java.security.Policy)`

  - ### setPolicy

    public static void setPolicy(Policy p)
    Deprecated, for removal: This API element is subject to removal in a future version.
    Sets the system-wide Policy object. This method first calls `SecurityManager.checkPermission` with a `SecurityPermission("setPolicy")` permission to ensure it's ok to set the Policy.
    Parameters:
      `p` - the new system Policy object.
    Throws:
      `SecurityException` - if a security manager exists and its `checkPermission` method doesn't allow setting the Policy.
    See Also:
      - `SecurityManager.checkPermission(Permission)`
      - `getPolicy()`

  - ### getInstance

    public static Policy getInstance(String type, Policy.Parameters params) throws NoSuchAlgorithmException
    Deprecated, for removal: This API element is subject to removal in a future version.
    Returns a Policy object of the specified type.

    This method traverses the list of registered security providers, starting with the most preferred Provider. A new Policy object encapsulating the PolicySpi implementation from the first Provider that supports the specified type is returned.

    Note that the list of registered providers may be retrieved via the `Security.getProviders()` method.

    Implementation Note:
      The JDK Reference Implementation additionally uses the `jdk.security.provider.preferred` `Security` property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by `Security.getProviders()`.
    Parameters:
      `type` - the specified Policy type. See the Policy section in the Java Security Standard Algorithm Names Specification for a list of standard Policy types.
      `params` - parameters for the Policy, which may be null.
    Returns:
      the new `Policy` object
    Throws:
      `IllegalArgumentException` - if the specified parameters are not understood by the `PolicySpi` implementation from the selected `Provider`
      `NoSuchAlgorithmException` - if no `Provider` supports a `PolicySpi` implementation for the specified type
      `NullPointerException` - if `type` is `null`
      `SecurityException` - if the caller does not have permission to get a `Policy` instance for the specified type.
    Since:
      1.6
    See Also:
      - `Provider`

  - ### getInstance

    public static Policy getInstance(String type, Policy.Parameters params, String provider) throws NoSuchProviderException, NoSuchAlgorithmException
    Deprecated, for removal: This API element is subject to removal in a future version.
    Returns a Policy object of the specified type.

    A new Policy object encapsulating the PolicySpi implementation from the specified provider is returned. The specified provider must be registered in the provider list.

    Note that the list of registered providers may be retrieved via the `Security.getProviders()` method.

    Parameters:
      `type` - the specified Policy type. See the Policy section in the Java Security Standard Algorithm Names Specification for a list of standard Policy types.
      `params` - parameters for the Policy, which may be null.
      `provider` - the provider.
    Returns:
      the new `Policy` object
    Throws:
      `IllegalArgumentException` - if the specified provider is `null` or empty, or if the specified parameters are not understood by the `PolicySpi` implementation from the specified provider
      `NoSuchAlgorithmException` - if the specified provider does not support a `PolicySpi` implementation for the specified type
      `NoSuchProviderException` - if the specified provider is not registered in the security provider list
      `NullPointerException` - if `type` is `null`
      `SecurityException` - if the caller does not have permission to get a `Policy` instance for the specified type
    Since:
      1.6
    See Also:
      - `Provider`

  - ### getInstance

    public static Policy getInstance(String type, Policy.Parameters params, Provider provider) throws NoSuchAlgorithmException
    Deprecated, for removal: This API element is subject to removal in a future version.
    Returns a Policy object of the specified type.

    A new Policy object encapsulating the PolicySpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.

    Parameters:
      `type` - the specified Policy type. See the Policy section in the Java Security Standard Algorithm Names Specification for a list of standard Policy types.
      `params` - parameters for the Policy, which may be null.
      `provider` - the Provider.
    Returns:
      the new `Policy` object
    Throws:
      `IllegalArgumentException` - if the specified `Provider` is `null`, or if the specified parameters are not understood by the `PolicySpi` implementation from the specified `Provider`
      `NoSuchAlgorithmException` - if the specified `Provider` does not support a `PolicySpi` implementation for the specified type
      `NullPointerException` - if `type` is `null`
      `SecurityException` - if the caller does not have permission to get a `Policy` instance for the specified type
    Since:
      1.6
    See Also:
      - `Provider`

  - ### getProvider

    public Provider getProvider()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Return the Provider of this Policy.

    This Policy instance will only have a Provider if it was obtained via a call to `Policy.getInstance`. Otherwise this method returns null.

    Returns:
      the Provider of this Policy, or null.
    Since:
      1.6

  - ### getType

    public String getType()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Return the type of this Policy.

    This Policy instance will only have a type if it was obtained via a call to `Policy.getInstance`. Otherwise this method returns null.

    Returns:
      the type of this Policy, or null.
    Since:
      1.6

  - ### getParameters

    public Policy.Parameters getParameters()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Return Policy parameters.

    This Policy instance will only have parameters if it was obtained via a call to `Policy.getInstance`. Otherwise this method returns null.

    Returns:
      Policy parameters, or null.
    Since:
      1.6

  - ### getPermissions

    public PermissionCollection getPermissions(CodeSource codesource)
    Deprecated, for removal: This API element is subject to removal in a future version.
    Return a PermissionCollection object containing the set of permissions granted to the specified CodeSource.

    Applications are discouraged from calling this method since this operation may not be supported by all policy implementations. Applications should solely rely on the `implies` method to perform policy checks. If an application absolutely must call a getPermissions method, it should call `getPermissions(ProtectionDomain)`.

    The default implementation of this method returns Policy.UNSUPPORTED_EMPTY_COLLECTION. This method can be overridden if the policy implementation can return a set of permissions granted to a CodeSource.

    Parameters:
      `codesource` - the CodeSource to which the returned PermissionCollection has been granted.
    Returns:
      a set of permissions granted to the specified CodeSource. If this operation is supported, the returned set of permissions must be a new mutable instance and it must support heterogeneous Permission types. If this operation is not supported, Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.

  - ### getPermissions

    public PermissionCollection getPermissions(ProtectionDomain domain)
    Deprecated, for removal: This API element is subject to removal in a future version.
    Return a PermissionCollection object containing the set of permissions granted to the specified ProtectionDomain.

    Applications are discouraged from calling this method since this operation may not be supported by all policy implementations. Applications should rely on the `implies` method to perform policy checks.

    The default implementation of this method first retrieves the permissions returned via `getPermissions(CodeSource)` (the CodeSource is taken from the specified ProtectionDomain), as well as the permissions located inside the specified ProtectionDomain. All of these permissions are then combined and returned in a new PermissionCollection object. If `getPermissions(CodeSource)` returns Policy.UNSUPPORTED_EMPTY_COLLECTION, then this method returns the permissions contained inside the specified ProtectionDomain in a new PermissionCollection object.

    This method can be overridden if the policy implementation supports returning a set of permissions granted to a ProtectionDomain.

    Parameters:
      `domain` - the ProtectionDomain to which the returned PermissionCollection has been granted.
    Returns:
      a set of permissions granted to the specified ProtectionDomain. If this operation is supported, the returned set of permissions must be a new mutable instance and it must support heterogeneous Permission types. If this operation is not supported, Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
    Since:
      1.4

  - ### implies

    public boolean implies(ProtectionDomain domain, Permission permission)
    Deprecated, for removal: This API element is subject to removal in a future version.
    Evaluates the global policy for the permissions granted to the ProtectionDomain and tests whether the permission is granted.
    Parameters:
      `domain` - the ProtectionDomain to test
      `permission` - the Permission object to be tested for implication.
    Returns:
      true if "permission" is a proper subset of a permission granted to this ProtectionDomain.
    Since:
      1.4
    See Also:
      - `ProtectionDomain`

  - ### refresh

    public void refresh()
    Deprecated, for removal: This API element is subject to removal in a future version.
    Refreshes/reloads the policy configuration. The behavior of this method depends on the implementation. For example, calling `refresh` on a file-based policy will cause the file to be re-read.

    The default implementation of this method does nothing. This method should be overridden if a refresh operation is supported by the policy implementation.