![]() Big decimal provides precise control over operations with decimal points. It extends number, and note that arithmetic operations do not get affected by the original object. Big decimal is especially useful with SQL databases. You can precisely calculate any precision you desire. Anyone who has tried to do precise arithmetic with a floating point type will realize the value of the big decimal type. Use it when an object is required but only a primitive is available, and do not use it in calculation or performance-sensitive code. And finally, use autoboxing and unboxing wisely. It can be fast but should not be used in places where performance is critical. There is a performance penalty due to the creation and garbage collection of objects. Trying to unbox a null results in a Null Pointer Exception at runtime. When working with autoboxing and unboxing, consider the following things. If the conversion goes the other way, this is called unboxing. That is an Int is converted into integer, or a double becomes a double and so on. Again, autoboxing is simply leveraging the compiler to convert from the primitive to its respective object wrapper class. With autoboxing, you can simply pass the primitive in and have the compiler perform the conversion for you at compile time. Why and when would autoboxing be used? Well, as seen here in the example, the list interface has an add method which takes a single input of type object. Autoboxing is the conversion process that Java uses at compile time to convert a primitive type into its corresponding object type using the correct object wrapper classes. However, due to the potential for number formatting exceptions, you should always perform these operations within a try-catch block to more gracefully handle such errors. This is an unchecked exception, and the code will compile without it. All the pass methods throw a Number Format Exception if the string does not hold a valid number. These are static methods, so they can be invoked without having to instantiate a wrapper class. Any time you need to convert from a string into the appropriate corresponding type, use the pass-x method, where x is the appropriate type. They allow primitives to be wrapped into object types, and they provide conversions to and from other types. Wrapper classes serve two primary purposes. Wrapper classes have been defined for each primitive: integer, long, short, double, float, byte, Boolean, and character. It still holds the primitive within but now has all of the characteristics of an object plus a host of methods that can act on the primitive. The Java language provides wrapper classes that wrap the primitive up into a real object. There are many times when a primitive isn't adequate. We'll go through defining enumerations, and finally, we'll show you static imports. We'll go through converting string representations of primitive numbers into their corresponding wrappers, converting string representation of primitive numbers into their primitive types. We'll cover items such as an introduction to the Wrapper Classes. In this lecture, we'll explore several of the Java utility classes and related techniques. Anyone interested in understanding the basics of the Java SDK.Anyone interested in basic Java application development and associated tooling.Software Architects interested in learning Java to design applications.Software Engineers interested in learning Java to develop applications.A basic understanding of the software development life cycle.A basic understanding of software development.And be able to confidently use System.out and System.format to print out strings. ![]() Format Strings using the formatter syntax.Be able to work with and define enumerations. ![]()
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