1. A method for assigning an annotation to a variable and a statement in a source code of a software application, the method comprising: generating, by a processor, an intermediate representation of the source code by parsing the source code, wherein the source code comprises a plurality of variables; identifying one or more instances of definition of the variable of the plurality of variables present in the intermediate representation; identifying, one or more instances of use of the variable in the intermediate representation; categorizing, by the processor, the variable into a group of variables based on: a) the one or more instances of definition of the variable, b) the one or more instances of use of the variable, c) a description of the variable, and d) mathematical operators defining a correlation between the variable and one or more other variables of the plurality of variables, wherein the description of the variable indicates a nature of data stored in the variable, and wherein the group of variables comprises variables storing data of similar nature; creating a data description table of the plurality of variables, wherein the data description table comprises the variable and the description of the variable; creating, by the processor, a data dictionary of the plurality of variables, wherein the data dictionary comprises the group of variables and the description of the variables present in the group of variables; and assigning, by the processor, the annotation to the variable present in the statement of the source code based on the data description table and the data dictionary, thereby assigning the annotation to the statement in the source code of the software application.