### Question:
Vectors { public static RealVector dense(int dimension) { return new ArrayRealVector(dimension); } private  Vectors(); static RealVector of(double... values); static RealVector dense(int dimension); static SparseRealVector sparse(int dimension); static SparseRealVector sparse(int dimension, int expectedSize); static RealVector like(RealVector vector);  }### Answer:
@Test public void testDense() { RealVector dense = Vectors.dense(10); assertEquals(10, dense.getDimension()); }