Make immutable Java object

My goal is to make a Java object immutable. I have a class Student. I coded it in the following way to achieve immutability:

public final class Student {

private String name;
private String age;

public Student(String name, String age) {
    this.name = name;
    this.age = age;
}

public String getName() {
    return name;
}

public String getAge() {
    return age;
}

}

My question is, what is the best way to achieve immutability for the Student class?

Answer

Your class is not immutable strictly speaking, it is only effectively immutable. To make it immutable, you need to use final:

private final String name;
private final String age;

Although the difference might seem subtle, it can make a significant difference in a multi-threaded context. An immutable class is inherently thread-safe, an effectively immutable class is thread safe only if it is safely published.