This work investigates the question of modular specification of generic Java classes and methods. The first part introduces a specification language for Java programs. In the second part the language is used to specify an array sorting algorithm by selection. The third and the fourth parts define a syntax proposal for the specification a generic Java programs, through two examples. The former is the specification of the generic method for sorting arrays which comes in the java.util.Arrays class of the Java API. The latter is the specification of the java.util.HashMap class and its use for memoization.