pass array values from method to method

Hello I am developing a mathematical library for java I wrote methods Matrix(), setMatrix (), getMatrix () is required to getmatrix() method returned the entire two-dimensional array more precisely all its values

static int[][] getMatrix(){//return matrix
        return matrix;
}//why returns a reference instead of an array value ? [[I@15db9742 only this

class Mathematik {

    private static int[][] matrix;
    private static int line_0;
    private static int column_0;

    static int Matrix(int line, int column){//Matrix
        for(int l=0; l<line; l++){//line
            for(int j=0; j<column; j++){//column
                line_0=l;
                column_0=j;
                matrix=new int[l][j];
            }
        }
        return matrix;
    }

    static int setMatrix(int num){//fill matrix
        for(int l=0; l<line_0; l++){//line
            for(int j=0; j<column_0; j++){//column
                matrix[l][j]=num;
            }
        }
        return 0;
    }

    static int[][] getMatrix(){//return matrix
        return matrix;
    }//why returns a reference instead of an array value ? [[I@15db9742 only this
}

class Activity{
    Mathematik A=new Mathematik();//call the class

    public static void main(Strin[] args){
        A.Matrix(3,3)//create matrix
        A.setMatrix(10)//to fill in the matrix

        System.out.println(""+A.getMatrix());//Writes the grid values to a string
    }
}

arrays [1a, 2a, 3a.....a]

the method getMatrix() is required to return all values of the array