Java™ How To Program (Early Objects), Tenth Edition

Java SE 7—Diamond (<>) Notation for Creating an Object of a Generic Class

Consider line 10 of Fig. 7.24:

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ArrayList<String> items = new ArrayList<String>();

Notice that ArrayList<String> appears in the variable declaration and in the class instance creation expression. Java SE 7 introduced the diamond (<>) notation to simplify statements like this. Using <> in a class instance creation expression for an object of a generic class tells the compiler to determine what belongs in the angle brackets. In Java SE 7 and higher, the preceding statement can be written as:

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ArrayList<String> items = new ArrayList<>();

When the compiler encounters the diamond (<>) in the class instance creation ...