Use of the final modifier in Java

Use of 1.final modifiers:

• Final can modify the variable, and after the final modified variable is assigned the initial value, it cannot be re-assigned.
• Final can modify the method, and the final modified method cannot be overridden.
• Final can modify the class, and the final decorated class cannot be inherited.

The above "grammar formulas" are still not enough to really master the final modifier.

2.final modified variable: The final modified instance variable must display the specified initial value, and the initial value can only be specified in the following three locations:

• Specifies the initial value when defining a final instance variable.
• Specifies the initial value for the final instance variable in a non-static initialization block.
• Specify the initial value for the final instance variable in the construction method.

　　

 PackageObjectstudy; Public classFinalinstancevaribaletest {Final intvar1 = 1;//Specifies the initial value when defining a final instance variable.     Final intvar2; Final intVar3; //Specifies the initial value for the final instance variable in a non-static initialization block. {var2= 2; }        //Specify the initial value for the final instance variable in the construction method.      Publicfinalinstancevaribaletest () { This. VAR3 = 3; }         Public Static voidMain (string[] args) {finalinstancevaribaletest finalinstancevaribaletest=Newfinalinstancevaribaletest ();        System.out.println (FINALINSTANCEVARIBALETEST.VAR1);        System.out.println (FINALINSTANCEVARIBALETEST.VAR2);    System.out.println (FINALINSTANCEVARIBALETEST.VAR3); }}

Use of the final modifier in Java