that class java provides keywordcalled thisfor such reference reference this is usefulfor exampleif we would like to pass the current object as parameter to some method another application of this is to reference field inside the current object that has name clash with variable defined in the current blockas shown in the program given in code fragment code fragment sample program illustrating the use of reference this to disambiguate between field of the current object and local variable with the same name when this program is executedit prints the followingthe dog local variable = the dog field an illustration of inheritance in java to make some of the notions above about inheritance and polymorphism more concretelet us consider some simple examples in java in particularwe consider series of several classes for stepping through and printing out numeric progressions numeric progression is sequence of numberswhere each number depends on one or more of the previous numbers for examplean arithmetic progression determines the next number by addition and geometric progression determines the next number by multiplication in