Titlebook: Java Quick Syntax Reference; Mikael Olsson Book 20131st edition Mikael Olsson 2013

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String,The . class in Java is a data type that can hold string literals. String is a reference data type, as are all non-primitive data types. This means that the variable contains an address to an object in the memory, and not the object itself. A . object is created in the memory, and the address to the object is returned to the variable.

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Inheritance,Inheritance allows a class to acquire the members of another class. In the example below, Apple inherits from Fruit. This is specified with the . keyword. Fruit then becomes the superclass of Apple, which in turn becomes a subclass of Fruit. In addition to its own members, Apple gains all accessible members in Fruit, except for its constructors.

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Overriding,A member in a subclass can redefine a member in its superclass. This is most often done to give instance methods new implementations.