Abstract: A system of the present invention includes a storage device for distinguishably storing old objects that are objects having existed for not less than a predetermined period since being generated and new objects that are objects having existed for less than the predetermined period since being generated. Then, a new object that has existed for less than the predetermined period since being generated is selected from the storage device, and an old object having the same content as the selected new object is searched for. If such an old object is not found, the selected new object is newly stored as an old object in the storage device. If the old object is found, a reference to the selected new object is integrated with a reference to the found old object. If the old object is stored, the reference to the selected new object is changed to a reference to the stored old object.

Abstract: A dynamic compiler program product, method, and device for sequentially compiling a partial computer program in a computer. The program product causes the computer to function as: an execution status acquisition unit for acquiring respective values of one or more pieces of current execution status information; a determination unit for reading, from the shared pool, the second list of the conditions associated with an executable instruction stream generated by compiling a partial program that is the same as a partial program to be compiled and determining whether respective values of corresponding pieces of current execution status information satisfy the conditions; and a dynamic compilation unit for generating an executable instruction stream by compiling the partial program to be compiled on the condition that a result of determination made by the determination unit is negative.

Abstract: A method of holding information for identifying a cause for an object becoming problematic and presenting the information to a user. The method ascertains the cause of memory consumption by a program in a computer system. This method includes: acquiring a first call path related to the creation of an object from a memory; acquiring a second call path related to the connection to the object from the memory; and determining a common part of the acquired first and second call paths, wherein the common part indicates the cause in the program.

Abstract: A method, computer system and computer program for optimizing the processing of a character string during execution of the program by using characteristic information that indicates a characteristic of the character string and is associated with the character string. The method includes the steps of determining, on the basis of a characteristic of a first character string and operation for the first character string, a characteristic information of at least one of the first character string and a second character string obtained as a result of the operation, and associating the characteristic information with the at least one character string.

Abstract: A string handling method, program, and information processing apparatus capable of reducing the amount of data stored in a storage. An information processing apparatus handles strings. The information processing apparatus includes a storage storing a group of strings including a plurality of strings each of which consists of a plurality of pieces of character data, a reference section which refers to a particular string in the group of strings, a character data detecting section which detects character data that is not referenced as the particular string in the group of strings, and a character data deleting section which deletes the detected character data from the group of strings.

Abstract: A data structure of a run-time object having a hash value field. The data structure allows an object allocation site to be traced from the run-time object, the object allocation site being a site in a program allocating the run-time object. A method for allowing an object allocation site to be traced from a run-time object includes embedding a value corresponding to the object allocation site in the program. A hash-value field includes the embedded value and the object identifier, and the tracing is performed by identifying the object allocation site that corresponds to the embedded value. A computer system for tracing an object allocation site includes a memory that stores the run-time object; an acquirer that acquires the value from a hash value field; and an identification unit that identifies the object allocation site that corresponds to the acquired value.

Abstract: It is one object of the present invention to provide a program execution method for performing greater optimization. A program execution apparatus according to the present invention performs a transfer from an interpreter process to a compiled code process in the course of the execution of a method. At this time, if no problem occurs when a transfer point is moved to the top of a loop, the transfer point for code is so moved. And when a transfer point is located inside a loop, a point that post-dominates the top of the loop and the transfer point is copied to a position immediately preceding the loop. Then, information for generating recalculation code is provided for the transfer point, and a recalculation is performed.

Abstract: A system of the present invention includes a storage device for distinguishably storing old objects that are objects having existed for not less than a predetermined period since being generated and new objects that are objects having existed for less than the predetermined period since being generated. Then, a new object that has existed for less than the predetermined period since being generated is selected from the storage device, and an old object having the same content as the selected new object is searched for. If such an old object is not found, the selected new object is newly stored as an old object in the storage device. If the old object is found, a reference to the selected new object is integrated with a reference to the found old object. If the old object is stored, the reference to the selected new object is changed to a reference to the stored old object.

Abstract: The same executable instruction stream as an executable instruction stream generated by a dynamic compiler is reproduced to facilitate debugging of the dynamic compiler. Provides compiler program for computer functioning as: an execution status obtaining section for obtaining an execution status of the program; a dynamic compilation section for compiling one of the partial programs to be executed during execution of the program; an execution status recording section for recording the execution status in a memory area allocated on a memory of the computer; a file reading section for reading a file containing contents of the memory area allocated on the memory; and a replay compilation section for compiling the one partial program on the basis of the execution status obtained from the file to generate the same executable instruction stream as the executable instruction stream generated by the dynamic compilation section during the execution of the program.

Abstract: Memory segments are allocated for a classloader to store class information, such as by selecting an allocation approach based on classloader type. In a first approach, in response to each request, a segment having a fixed size is allocated. In a second approach, in response to a first request, a first segment having a size equal to an amount of memory needed to store information related to the request is allocated. In response to a second request, a second segment having a second size is allocated, and in response to a third request, a third segment having a third size greater than the second size is allocated. In a third approach, in response to the first request, a first segment having a first size is allocated. In response to a second request, a second segment having a second size greater than the first size is allocated.

Abstract: A string handling method, program, and information processing apparatus capable of reducing the amount of data stored in a storage. An information processing apparatus handles strings. The information processing apparatus includes a storage storing a group of strings including a plurality of strings each of which consists of a plurality of pieces of character data, a reference section which refers to a particular string in the group of strings, a character data detecting section which detects character data that is not referenced as the particular string in the group of strings, and a character data deleting section which deletes the detected character data from the group of strings.

Abstract: Memory segments are allocated for a classloader to store class information, such as by selecting an allocation approach based on classloader type. In a first approach, in response to each request, a segment having a fixed size is allocated. In a second approach, in response to a first request, a first segment having a size equal to an amount of memory needed to store information related to the request is allocated. In response to a second request, a second segment having a second size is allocated, and in response to a third request, a third segment having a third size greater than the second size is allocated. In a third approach, in response to the first request, a first segment having a first size is allocated. In response to a second request, a second segment having a second size greater than the first size is allocated.

Abstract: A method and system are provided for starting a new JAVA application while eliminating overhead associated therewith. The new JAVA application is created from a memory image of an initialized JAVA application. The memory image of the process which is executing the initialized JAVA application is copied to enable the memory image to be observed by the new JAVA application. In addition, to copying the memory image, the states of system resources and operating system monitors not present in the copied memory image are recreated on the JAVA application.

Abstract: The same executable instruction stream as an executable instruction stream generated by a dynamic compiler is reproduced to facilitate debugging of the dynamic compiler. Provides compiler program for computer functioning as: an execution status obtaining section for obtaining an execution status of the program; a dynamic compilation section for compiling one of the partial programs to be executed during execution of the program; an execution status recording section for recording the execution status in a memory area allocated on a memory of the computer; a file reading section for reading a file containing contents of the memory area allocated on the memory; and a replay compilation section for compiling the one partial program on the basis of the execution status obtained from the file to generate the same executable instruction stream as the executable instruction stream generated by the dynamic compilation section during the execution of the program.

Abstract: To perform efficient execution of a bytecode by combining an interpreter and a compiler. At a time of a bytecode execution by an interpreter, if an instruction to be executed is a backward conditional branch instruction, it is determined whether the backward conditional branch instruction is a back edge of a loop. And if it is determined the instruction is a back edge of a loop, the number of the loop iteration is estimated and stored into a storage. A bytecode execution mode is selected according to the estimated number of the loop iteration. This execution mode comprises the modes of immediately compiling a method including a loop, and having the interpreter execute a bytecode.

Abstract: The present invention provides a compiler that can compile Java byte code at high speed while employing only limited resources. The technique converts byte code into intermediate code that employs, as an opcode, an address of an execution routine that corresponds to a byte code, and executes the execution routines in a sequential order corresponding to that of the intermediate code. The length of the intermediate code is constant and the bit location of the opcode is also constant. The execution routine is stored in sequential areas in a memory, and an offset of the execution routine group from the head address of the sequential memory area is employed as an opcode.