Abstract: Techniques for determining and displaying error messages including a cause of an error generated because two types are not members of the same nest are disclosed. The system detects, at runtime, an instruction in a first type that attempts to access a private member of a second type. The system evaluates one or more nestmate criteria to determine whether the first type and the second type are within a same nest. A nest host corresponding to the nest specifies each nest member of the nest, and each nest member specifies an association with the nest. Responsive to determining that a particular nestmate criterion is not met, the system determines that the first type and the second type are not within the same nest and records or displays data identifying the particular nestmate criterion that has not been met, and throws an access error.

Abstract: Techniques for determining and displaying error messages including a cause of an error generated because two types are not members of the same nest are disclosed. The system detects, at runtime, an instruction in a first type that attempts to access a private member of a second type. The system evaluates one or more nestmate criteria to determine whether the first type and the second type are within a same nest. A nest host corresponding to the nest specifies each nest member of the nest, and each nest member specifies an association with the nest. Responsive to determining that a particular nestmate criterion is not met, the system determines that the first type and the second type are not within the same nest and records or displays data identifying the particular nestmate criterion that has not been met, and throws an access error.

Abstract: A runtime environment generates a proxy class in response to detecting a request for a proxy object. The proxy class implements a set of interfaces specified by the request for the proxy object. The runtime environment selects or generates a proxy module, in a module system, to include the proxy class. The runtime environment exposes interfaces from other modules to the proxy module using a qualified export that does not expose the interfaces to modules other than the proxy module. The runtime environment does not expose the proxy class, of the proxy module, to other modules in the module system.

Abstract: A module (m1) is allowed to gain private reflective access to any class in any module (C2 in m2), if and only if m2 grants to m1 deep reflective access for C2. A caller class may invoke a method to generate a second lookup object associated with a second principal class based on a first lookup object associated with a first principal class. The method is successfully executed only if (a) an access mode of the first lookup object allows for teleporting with private reflective access and (b) a module including the second principal class grants to a module including the first principal class deep reflective access for the second principal class. The second lookup object drops the access mode allowing for teleporting with private reflective access. Hence reflective access is confined within the limits imposed by module boundaries, as relaxed by access agreements between pairs of modules. The bilateral agreements are not transferable to other modules.

Abstract: Techniques for determining and displaying error messages including a cause of an error generated because two types are not members of the same nest are disclosed. The system detects, at runtime, an instruction in a first type that attempts to access a private member of a second type. The system evaluates one or more nestmate criteria to determine whether the first type and the second type are within a same nest. A nest host corresponding to the nest specifies each nest member of the nest, and each nest member specifies an association with the nest. Responsive to determining that a particular nestmate criterion is not met, the system determines that the first type and the second type are not within the same nest and records or displays data identifying the particular nestmate criterion that has not been met, and throws an access error.

Abstract: A module (m1) is allowed to gain private reflective access to any class in any module (C2 in m2), if and only if m2 grants to m1 deep reflective access for C2. A caller class may invoke a method to generate a second lookup object associated with a second principal class based on a first lookup object associated with a first principal class. The method is successfully executed only if (a) an access mode of the first lookup object allows for teleporting with private reflective access and (b) a module including the second principal class grants to a module including the first principal class deep reflective access for the second principal class. The second lookup object drops the access mode allowing for teleporting with private reflective access. Hence reflective access is confined within the limits imposed by module boundaries, as relaxed by access agreements between pairs of modules. The bilateral agreements are not transferable to other modules.

Abstract: A runtime environment generates a proxy class in response to detecting a request for a proxy object. The proxy class implements a set of interfaces specified by the request for the proxy object. The runtime environment selects or generates a proxy module, in a module system, to include the proxy class. The runtime environment exposes interfaces from other modules to the proxy module using a qualified export that does not expose the interfaces to modules other than the proxy module. The runtime environment does not expose the proxy class, of the proxy module, to other modules in the module system.

Abstract: A runtime environment generates a proxy class in response to detecting a request for a proxy object. The proxy class implements a set of interfaces specified by the request for the proxy object. The runtime environment selects or generates a proxy module, in a module system, to include the proxy class. The runtime environment exposes interfaces from other modules to the proxy module using a qualified export that does not expose the interfaces to modules other than the proxy module. The runtime environment does not expose the proxy class, of the proxy module, to other modules in the module system.

Abstract: A runtime environment identifies a request for a proxy object whose class implements a plurality of interfaces. Responsive to the request, the runtime object generates a class for the proxy object. Generating the class comprises determining that two or more interfaces, of the plurality of interfaces, define a respective method body with a same method signature. Responsive to determining that the two or more interfaces define a respective method body with a same method signature, the runtime environment may (a) omit a method body, in the class, for a particular method corresponding to the method signature, (b) include a method body that triggers a runtime error, or (c) include a method body that includes operations to select a default method declared in one of the two or more interfaces.

Abstract: Techniques for managing split packages in a module system are disclosed. A code conflict exists between two packages, in different modules, based at least in part on the packages being named identically and including executable code. No code conflict exists between two other identically-named packages, in different modules, based at least in part on the packages not including any executable code. Managing split packages may be based, at least in part, on module membership records associated with the modules.

Abstract: Techniques for managing split packages in a module system are disclosed. A code conflict exists between two packages, in different modules, based at least in part on the packages being named identically and including executable code. No code conflict exists between two other identically-named packages, in different modules, based at least in part on the packages not including any executable code. Managing split packages may be based, at least in part, on module membership records associated with the modules.

Abstract: A runtime environment generates a proxy class in response to detecting a request for a proxy object. The proxy class implements a set of interfaces specified by the request for the proxy object. The runtime environment selects or generates a proxy module, in a module system, to include the proxy class. The runtime environment exposes interfaces from other modules to the proxy module using a qualified export that does not expose the interfaces to modules other than the proxy module. The runtime environment does not expose the proxy class, of the proxy module, to other modules in the module system.

Abstract: A runtime environment generates a proxy class in response to detecting a request for a proxy object. The proxy class implements a set of interfaces specified by the request for the proxy object. The runtime environment selects or generates a proxy module, in a module system, to include the proxy class. The runtime environment exposes interfaces from other modules to the proxy module using a qualified export that does not expose the interfaces to modules other than the proxy module. The runtime environment does not expose the proxy class, of the proxy module, to other modules in the module system.

Abstract: A runtime environment identifies a request for a proxy object whose class implements a plurality of interfaces. Responsive to the request, the runtime object generates a class for the proxy object. Generating the class comprises determining that two or more interfaces, of the plurality of interfaces, define a respective method body with a same method signature. Responsive to determining that the two or more interfaces define a respective method body with a same method signature, the runtime environment may (a) omit a method body, in the class, for a particular method corresponding to the method signature, (b) include a method body that triggers a runtime error, or (c) include a method body that includes operations to select a default method declared in one of the two or more interfaces.

Abstract: A runtime environment generates a proxy class in response to detecting a request for a proxy object. The proxy class implements a set of interfaces specified by the request for the proxy object. The runtime environment selects or generates a proxy module, in a module system, to include the proxy class. The runtime environment exposes interfaces from other modules to the proxy module using a qualified export that does not expose the interfaces to modules other than the proxy module. The runtime environment does not expose the proxy class, of the proxy module, to other modules in the module system.