Create a new class com.tutego.money.MonetaryAmount. It should store a monetary amount to two decimal places. The object is immutable and must be thread-safe and also Serializable. Use the following incomplete but compilable template:

public class MonetaryAmount {

 private MonetaryAmount() { }

 // create immutable MonetaryAmount objects by factory method
 public static MonetaryAmount of( double value ) { return null; }

 // return the value
 public double value() { return 0; }
 public String toString() { return ""; }

 // MonetaryAmount objects should be able to be compared with equals(Object o)
 public boolean equals( Object o ) { return false; }

 //
 public MonetaryAmount add( MonetaryAmount value ) { return null; }
 public MonetaryAmount subtract( MonetaryAmount value ) { return null; }
}

Write a short Javadoc. Negative monetary amounts must not exist and must be blocked via an exception. 0 is allowed. The toString format is: no thousand separators, always two decimal places, decimal separator always the dot.

Is there a method missing that should always be used for symmetry reasons?

Create a new class com.tutego.money.MonetaryAmountTest for the test case. In what package do the class belong? Does the IDE support us?

Implement appropriate test methods. What do we need to test?

Implement all methods of the class MonetaryAmount.

Are our data types chosen wisely? Do we need to correct a choice?