Contents
How can we prevent immutable class?
How to preserve Immutability? There are two ways to avoid this problem, first, don’t provide getters to mutable objects if you can avoid it. If you must, then consider returning a copy or clone of the mutable object. If you are returning a collection, you could wrap it as an unmodifiable collection.
Can immutable class have constructor?
Example to create Immutable class It have one final datamember, a parameterized constructor and getter method. The above class is immutable because: The instance variable of the class is final i.e. we cannot change the value of it after creating an object.
How can we prevent immutable class from serialization?
If an immutable object was serialized, its raw bytes could be modified so that upon deserialization the object is no longer the same. This can’t be prevented completely. Encryption, checksums, and CRC’s will help to prevent this though.
How do you protect Singleton from serialization?
Overcome Cloning issue:- To overcome this issue, override clone() method and throw an exception from clone method that is CloneNotSupportedException. Now whenever user will try to create clone of singleton object, it will throw exception and hence our class remains singleton.
Can immutable class be serializable?
It turns out you can serialize immutable objects because there’s no requirement that there be a public no-argument constructor.
Can an immutable class have a zero argument?
If you really mean no zero argument constructors (including private) and forbid access to static global variables and require immutability, then I claim that your object cannot hold any non-constant data, only behaviour (e.g., strategy pattern, as others mentioned).
What does the @ immutable annotation mean in Java?
The @Immutable annotation seems to be something totally different for auto class generation and not part of standard Java. Looking at the documentation of the String class (bold text is something I did): The String class represents character strings. All string literals in Java programs, such as “abc”, are implemented as instances of this class.
Why is the string class immutable in Java?
Because String objects are immutable they can be shared. As you can see, there is no particular labeling or other markers, however, they do specify in the JavaDoc describing the class that the String class represents a constant, immutable object.
Is there an @ immutable keyword in Javadoc?
It seems there is no @immutable keyword in Javadoc. The @Immutable annotation seems to be something totally different for auto class generation and not part of standard Java. Looking at the documentation of the String class (bold text is something I did):