Oracle International Corporation

Paul Sandoz

Alexander R Buckley

Chris Hegarty

Alan Bateman

Mark B Reinhold

Brian Goetz

John Robert Rose

According to one technique, a virtual machine generates an object configured to provide secure access to memory through one or more memory fencing operations. Through the object, the virtual machine receives a call that indicates a memory location and specifies a particular memory fencing operation of the one or more memory fencing operations to perform with respect to the memory location. The virtual machine causes performance of the particular memory fencing operation with respect to the memory location.

Variable handles

Access to a module element within a first module by a second module is prohibited if the module element within the first module has not been exposed to the second module. If a particular module element within a first module has been exposed to a second module, then access to the particular module element by the second module may or may not be allowed depending on: (a) whether the particular module element has been declared with a public or non-public access modifier, (b) whether a second exposed module element, which includes the particular module element, has been declared with a public or non-public access modifier, (c) a level of access associated with the operation that attempts to access the particular module element of the first module, and/or (d) whether an accessibility override configuration is set for accessing the particular module element.

Restrictive access control for modular reflection

Permissive access control for modular reflection

According to one technique, a virtual machine identifies a first instruction to create a variable handle instance, the first instruction including declaration information that identifies a type of receiver and a variable held by the receiver to which the variable handle instance is configured to provide access. If access to the variable is permissible, the virtual machine creates the variable handle instance comprising constrained functions configured to execute constrained operations on a memory location of the variable. The virtual machine identifies a second instruction that specifies a call to a particular constrained, wherein the second instruction specifies the receiver or is implicitly bound to the receiver. The virtual machine identifies a particular memory location where the instance of the variable is stored and performs the particular constrained function with respect to the particular memory location.

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Le Versoud, France

Paul Sandoz