Sun Microsystems, Inc.

Oracle America, Inc.

Antero K P Taivalsaari

William F Pittore

Randall B Smith

Bernd J W Mathiske

Nik Shaylor

One embodiment of the present invention provides a system that resolves references in an in-place execution file for a platform-independent virtual machine into physical addresses. During operation, the system receives an in-place execution file in which references have been replaced with in-place encoded metadata specifying attributes of the references. The system then resolves a reference by obtaining in-place encoded metadata for the reference from a location in the in-place execution file, using the in-place encoded metadata to determine an address of an associated referent, and then replacing the in-place encoded metadata at the location in the in-place execution file with the address of the referent.

Method and apparatus for facilitating intermediate linking of binary files in a virtual machine

One embodiment of the present invention provides a system that facilitates loading of an in-place executable file into a virtual machine. The system operates by loading the in-place executable file into the virtual machine, where the in-place executable file contains internal pointers that point to memory locations within the in-place executable file, and a target memory address that specifies a target location in memory where the in-place executable file is configured to be loaded. The system then determines an actual memory address at which the in-place executable file is actually loaded. If the actual memory address and the target memory address are different, the system generates an offset value, which is the difference between the actual memory address and the target memory address. Finally, the system adjusts each internal pointer within the in-place executable file by the offset value so that the internal pointers point to intended locations inside the in-place executable file.

Method and apparatus for loading relocatable in-place executable files in a virtual machine

One embodiment of the present invention provides a system that facilitates efficiently resolving symbolic references in a virtual machine to support in-place execution. During operation, the system loads an in-place executable file into the virtual machine, and receives a pointer that points to an unresolved symbol value in the in-place executable file. This unresolved symbol value includes an offset value that points to a subsequent unresolved symbol value in a chain of unresolved symbol values within the in-place executable file, and a token value that can be used to look up a corresponding resolved reference value in an unresolved symbol table. The system then uses the token value to look up the corresponding resolved reference in the unresolved symbol table, and replaces the unresolved symbol value with the corresponding resolved reference.

Method and apparatus for efficiently resolving symbolic references in a virtual machine

One embodiment of the present invention provides a system that facilitates performing proximity-based addressing in a platform-independent virtual machine. During execution of a program on the platform-independent virtual machine, the system receives an instruction and a parameter associated with the instruction that can be used to generate a reference to a program element associated with the instruction. Next, the system examines information encoded within the parameter to determine a proximity of the reference, and then uses the parameter to generate the reference to the program element, wherein the proximity of the reference determines how the reference is generated from the parameter.

Proximity-based addressing for supporting in-place execution in virtual machines

One embodiment of the present invention provides a method for increasing performance of code executing on a platform-independent virtual machine. The method operates by receiving a request to resolve an entry in a symbol table at run-time, wherein resolving the entry requires multiple lookups into the symbol table. It next determines if the entry has previously been resolved. If so, the system returns a direct pointer to a runtime structure associated with the entry, which was returned during a previous resolution of the entry. If not, the system resolves the entry through multiple lookups into the symbol table to produce a direct pointer to the runtime structure, and replaces the entry with the direct pointer. In a variation on the above embodiment, the symbol table assumes the form of a constant pool within an object-oriented class file defined within the JAVA programming language. The present invention speeds up constant pool resolution substantially without requiring a significant amount of additional space. Therefore, the present invention is especially valuable for embedded JAVA systems or other applications that have strict size limitations.

Optimizing symbol table lookups in platform-independent virtual machines

One embodiment of the present invention provides a system for viewing objects on a display that allows a user to scroll through the objects by varying a non-positional display attribute of the objects. This non-positional display attribute may include attributes such as transparency, fadedness and size. The system operates by receiving an intrinsic value for an object, which specifies a value for a display attribute associated with the object. The system also receives a reference value for the display attribute against which intrinsic values for objects are compared. This reference value may be received from a user through a scroll bar that is manipulated by the user. The system uses the intrinsic value and the reference value to compute a display value for the object. Next, the object is displayed using the display value to specify the non-positional display attribute for the object. Thus, in one embodiment of the present invention, objects that have an intrinsic value equal to reference value are displayed normally (opaquely) without any fading. Other objects that have a display value close the reference value are displayed translucently, giving the impression that objects are &ldquo;emerging from the fog&rdquo; or gradually &ldquo;fading away.&rdquo; Objects with a large difference between the intrinsic value of the object and the reference value are not displayed at all.

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Siivikkala, Finland

Antero K P Taivalsaari