Create a class named Rock that acts as a superclass for rock samples collected and catalogued by a natural history museum. The Rock class contains fields for a number of samples, a description of the type of rock, and the weight of the rock in grams. Include a constructor that accepts parameters for the sample number and weight. The Rock constructor sets the description value to Unclassified. Include get methods for each field. Create three child classes named IgneousRock, SedimentaryRock, and MetamorphicRock. The constructors for these classes require parameters for the sample number and weight. Search the Internet for a brief description of each rock type and assign it to the description field. Create an application that instantiates an object of each type and demonstrate that the methods work appropriately. Save the files as Rock.java, IgneousRock.java, SedimentaryRock.java, MetamorphicRock.java, and DemoRocks.java.