FinalVariableExample.java

class TestFinalVariable {
    public final int foo;
    // If variable is static and final, it must be initialized right away.
    public static final int bar = 10;

    //In constructor, initialization of final variable is allowed, as compiler knows that the constructor can only be called 1 time per object.
    //Static variables can not be initialized even in constructor, as they are shared between multiple objects and that's why multiple object
    //initialization can updathe the same copy of final variable, which is not allowed and thus static final variable must be initialized on declaration
    TestFinalVariable(int foo) {
        this.foo = foo;
    }

    public void updateFinal(int foo) {
        //In method initialization of final variable is not allowed, as compiler knows that the method can be called multiple times.
        // this.foo = foo;
    }
}

public class FinalVariableExample {
    public static void main(String[] args) {
        TestFinalVariable testFinalVariable = new TestFinalVariable(28);
        System.out.println(testFinalVariable.foo);
    }
}