Sun Microsystems, Inc.

Oracle International Corporation

Oracle America, Inc.

Richard D Tuck

Nedim Fresko

Dean R E Long

Peter W Madany

Frank N Yellin

John Robert Rose

Christopher Jordan Plummer

Dean R Long

Hania Gajewska

Dean RE Long

A hybrid system is provided. The system includes a computing device implementing a first application execution environment (AEE) and a second AEE. The first AEE is configured to be isolated from the second AEE. The first software application associated with the first AEE is configured to be processed on the first AEE such that the first software application is denied direct access to the second AEE. A second software application associated with the second AEE is configured to be processed on the second AEE such that the second software application is denied direct access to the first AEE.

Hybrid system implementing distinct and co-existing application execution environments and methods for implementing the same

Methods and apparatus for reducing the number of runtime checks performed during the execution of a virtual machine. According to one aspect of the present invention, a computer system includes a preloader, a compiler, and a virtual machine. The preloader is arranged to determine whether a bytecode makes an active reference to a class which requires an execution of a static initializer, and is also arranged to determine if the class has a superclass which requires the execution of the static initializer. The compiler is arranged to accept a source file generated by the preloader as input and to produce an object file, and the virtual machine is arranged to execute the object file.

Method and apparatus for rewriting bytecodes to minimize runtime checks

Methods and apparatus for creating compacted method signatures from method signature representations in Java&trade; class files are disclosed. The use of compacted signatures reduces the amount of memory space occupied by the signatures and, further, improve the efficiency with which a virtual machine may operate. According to one aspect of the present invention, a method a method for creating a compact representation of a method signature using a virtual machine includes creating 4-bit representations for each of a first parameter, a separator, and a return type included in the method signature. Once the 4-bit representation are created, the representations are packed into a word. In one embodiment, the word is a 32-bit word. In such an embodiment, the 32-bit word may be a 32-bit integer.

Method and apparatus for implementing compact type signatures in a virtual machine environment

A method and apparatus for pre-processing and packaging class files. Embodiments remove duplicate information elements from a set of class files to reduce the size of individual class files and to prevent redundant resolution of the information elements. Memory allocation requirements are determined in advance for the set of classes as a whole to reduce the complexity of memory allocation when the set of classes are loaded. The class files are stored in a single package for efficient storage, transfer and processing as a unit. In an embodiment, a pre-processor examines each class file in a set of class files to locate duplicate information in the form of redundant constants contained in a constant pool. The duplicate constant is placed in a separate shared table, and all occurrences of the constant are removed from the respective constant pools of the individual class files. During pre-processing, memory allocation requirements are determined for each class file, and used to determine a total allocation requirement for the set of class files. The shared table, the memory allocation requirements and the reduced class files are packaged as a unit in a multi-class file.

Method and apparatus for pre-processing and packaging class files

A task executing at a server receives a request to package program code for remote execution on a client, and determines the software components that already reside at the client. The task uses this information to formulate a set of instructions to another task that creates the package. The created package is transmitted to the client, and program execution begins.

Methods and apparatus for packaging a program for remote execution

A linkage editor executing at a server receives instructions for packaging software components that are required for program execution at a client. The linkage editor generates an output file by iteratively analyzing the program for references to other software components and extracting those components from their parent classes. The linkage editor sends the completed output file to an interface task, which transmits it to the client.

Methods and apparatus for linking a program for remote execution

The disclosed system represents an improvement over conventional systems for initializing static arrays by reducing the amount of code executed by the virtual machine to statically initialize an array. To realize this reduction, when consolidating class files, the preloader identifies all &lt;clinit&gt; methods and play executes these methods to determine the static initialization performed by them. The preloader then creates an expression indicating the static initialization performed by the &lt;clinit&gt; method and stores this expression in the .mclass file, replacing the &lt;clinit&gt; method. As such, the code of the &lt;clinit&gt; method, containing many instructions, is replaced by a single expression instructing the virtual machine to perform static initialization, thus saving a significant amount of memory. The virtual machine is modified to recognize this expression and perform the appropriate static initialization of an array.

Method and system for performing static initialization

A method of cross-compiling computer programs includes the step of extracting constants from an inheriting computer program written in a first computer language. The extracted constants refer to a generating computer program written in a second computer language. A new program in the second computer language is then created using the constants. The new program is then compiled for a target computer to ascertain compiled constant values. The compiled constant values are then substituted into the inheriting computer program to produce a final inheriting computer program.

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San Francisco, CA, United States of America

Richard D Tuck