1 if the java instruction corresponding to the current java class method meets the preset condition of the portable instruction executes step 114 if the java instruction corresponding to the current java class method does not meet the preset condition of the portable instruction in step b 1 the java virtual machine displays the current java class method of the java file and the java instruction corresponding to the current java class method in step c 1 the java virtual machine determines the number of java class methods which have been parsed is more than a total number of java class methods executes step d 1 if the number of the java class methods which have been parsed is more than the total number of the java class methods makes a next java class method as the current java class method and returns to execute step 104 if the number of the java class methods which have been parsed is not more than the total number of the java class methods in step d 1 the java virtual machine receives a choice of a user for displayed java class methods and java instructions corresponding to the java class methods and according to the.