### Question:
Vectors { public static SparseRealVector sparse(int dimension) { return new OpenMapRealVector(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 testSparse() { RealVector sparse = Vectors.sparse(Integer.MAX_VALUE); assertEquals(Integer.MAX_VALUE, sparse.getDimension()); assertEquals(0.0, sparse.getEntry(0)); }