[java] In Java, what purpose do the keywords `final`, `finally` and `finalize` fulfil?

The meaning of final in java is: -applied to a variable means that the respective variable once initialized can no longer be modified

private final double numer = 12;

If you try to modify this value, you will get an error.

-applied to a method means that the respective method can't be override

 public final void displayMsg()
    {
        System.out.println("I'm in Base class - displayMsg()");
    }

But final method can be inherited because final keyword restricts the redefinition of the method.

-applied to a class means that the respective class can't be extended.

class Base
{

    public void displayMsg()
    {
        System.out.println("I'm in Base class - displayMsg()");
    }
}

The meaning of finally is :

class TestFinallyBlock{  
  public static void main(String args[]){  
  try{  
   int data=25/5;  
   System.out.println(data);  
  }  
  catch(NullPointerException e){System.out.println(e);}  
  finally{System.out.println("finally block is always executed");}  
  System.out.println("rest of the code...");  
  }  
} 

in this exemple even if the try-catch is executed or not, what is inside of finally will always be executed. The meaning of finalize:

class FinalizeExample{  
public void finalize(){System.out.println("finalize called");}  
public static void main(String[] args){  
FinalizeExample f1=new FinalizeExample();  
FinalizeExample f2=new FinalizeExample();  
f1=null;  
f2=null;  
System.gc();  
}}  

before calling the Garbage Collector.

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