A communication terminal comprising: a transmitting/receiving unit constituted of an antenna and a communication control circuit and configured to perform radio communication with base stations of a mobile data communication network; and a downloading means configured to download a Java application from a download server, using the transmitting/receiving unit; a SRAM configured to store the downloaded Java application, a history of outgoing calls comprising telephone numbers of communication nodes called by the communication terminal, a history of incoming calls comprising telephone numbers of communication nodes from which calls were received by the communication terminal, and telephone directory data; a ROM configured to store software providing an execution environment for the downloaded Java application, the software including an operating system, a Java application manager, and a Java K virtual machine; wherein the Java K virtual machine is configured to process the downloaded Java application, the processing of the Java application being executed execution unit by execution unit, and wherein the Java K virtual machine is further configured to, before an execution unit in the processing of the Java application is executed, determine whether the execution of the execution unit requires a call origination to a communication node by the transmitting/receiving unit, and if it is determined, by the Java K virtual machine, that the call origination is required, the Java application manager is configured to select, according to an attribute of the downloaded Java application, one or more of the history of outgoing calls, the history of incoming calls and the telephone directory data as a selected specific group of telephone numbers, and to determine whether a telephone number of the communication node is registered in the selected specific group of telephone numbers, if it is determined, by the Java application manager, that the telephone number of the communication node is registered in the selected specific group of telephone numbers, the Java application manager is further configured to determine that the call origination is granted and instruct the Java K virtual machine to execute the execution unit requiring the call origination, if it is determined, by the Java application manager, that the telephone number of the communication node is not registered in the selected specific group of telephone numbers, the Java application manager is further configured to determine that the call origination is not granted and instruct the Java virtual K machine to display a message on a liquid crystal display of the communication terminal indicating that the call origination cannot be granted, together with another message indicating that a user's instruction is necessary to perform the call origination. a transmitting/receiving unit constituted of an antenna and a communication control circuit and configured to perform radio communication with base stations of a mobile data communication network; and a downloading means configured to download a Java application from a download server, using the transmitting/receiving unit; a SRAM configured to store the downloaded Java application, a history of outgoing calls comprising telephone numbers of communication nodes called by the communication terminal, a history of incoming calls comprising telephone numbers of communication nodes from which calls were received by the communication terminal, and telephone directory data; a ROM configured to store software providing an execution environment for the downloaded Java application, the software including an operating system, a Java application manager, and a Java K virtual machine; wherein the Java K virtual machine is configured to process the downloaded Java application, the processing of the Java application being executed execution unit by execution unit, and wherein the Java K virtual machine is further configured to, before an execution unit in the processing of the Java application is executed, determine whether the execution of the execution unit requires a call origination to a communication node by the transmitting/receiving unit, and if it is determined, by the Java K virtual machine, that the call origination is required, the Java application manager is configured to select, according to an attribute of the downloaded Java application, one or more of the history of outgoing calls, the history of incoming calls and the telephone directory data as a selected specific group of telephone numbers, and to determine whether a telephone number of the communication node is registered in the selected specific group of telephone numbers, if it is determined, by the Java application manager, that the telephone number of the communication node is registered in the selected specific group of telephone numbers, the Java application manager is further configured to determine that the call origination is granted and instruct the Java K virtual machine to execute the execution unit requiring the call origination, if it is determined, by the Java application manager, that the telephone number of the communication node is not registered in the selected specific group of telephone numbers, the Java application manager is further configured to determine that the call origination is not granted and instruct the Java virtual K machine to display a message on a liquid crystal display of the communication terminal indicating that the call origination cannot be granted, together with another message indicating that a user's instruction is necessary to perform the call origination.