output

Value added to the matrix: 0_0
Value added to the matrix: 0_1
Value added to the matrix: 0_2
Value added to the matrix: 1_0
Value added to the matrix: 1_1
Value added to the matrix: 1_2
Value added to the matrix: 2_0
Value added to the matrix: 2_1
Value added to the matrix: 2_2
Found: 1_2

TestGenerics.java

import java.util.Comparator;
import java.util.Objects;
import java.util.function.Consumer;

public class TestGenerics {

    public static class A<T> {
        private T var;
        public A(T elm) {
            var = elm;
        }

        public void fun(T[][] foo, Comparator<T> comparator, Consumer<T> invoke) {
            for(int r=0 ; r < foo.length; r++) {
                for (int c = 0; c < foo[r].length; c++) {
                    if(Objects.compare(foo[r][c], var, comparator) == 0) {
                        invoke.accept(foo[r][c]);
                    }
                }
            }
        }
    }

    public static void main(String args[]) {
        A<String> a = new A<String>("1_2");
        String[][] matrix = new String[3][3];
        for(int r=0 ; r < matrix.length; r++) {
            for (int c = 0; c < matrix[r].length; c++) {
                matrix[r][c] = r + "_" + c;
                System.out.println("Value added to the matrix: " + matrix[r][c]);
            }
        }

        a.fun(matrix, String::compareTo, found -> {
            // Here you execute anything with "var"
            System.out.println("Found: " + found);
        });
    }

}