@SuppressWarnings("fallthrough")
    public Matrix3f set(int i, int j, float value) {
        switch (i) {
            case 0:
                switch (j) {
                    case 0:
                        m00 = value;
                        return this;
                    case 1:
                        m01 = value;
                        return this;
                    case 2:
                        m02 = value;
                        return this;
                }
            case 1:
                switch (j) {
                    case 0:
                        m10 = value;
                        return this;
                    case 1:
                        m11 = value;
                        return this;
                    case 2:
                        m12 = value;
                        return this;
                }
            case 2:
                switch (j) {
                    case 0:
                        m20 = value;
                        return this;
                    case 1:
                        m21 = value;
                        return this;
                    case 2:
                        m22 = value;
                        return this;
                }
        }

        logger.warning("Invalid matrix index.");
        throw new IllegalArgumentException("Invalid indices into matrix.");
    }
Sets the specified element.

@param i the row index (0, 1, or 2)
@param j the column index (0, 1, or 2)
@param value desired value for the element at (i, j)
@return the (modified) current instance (for chaining)
@throws IllegalArgumentException if either index isn't 0, 1, or 2
jme3-core/src/main/java/com/jme3/math/Matrix3f.java