How can Singleton be prevented?

Singleton abuse can be avoided by looking at the problem from a different angle. Suppose an application needs only one instance of a class and the application configures that class at startup: Why should the class itself be responsible for being a singleton?

What are values of reflection?

Dec 16, 2013 The Value of Reflection. Reflection brings learning to life. Reflective practice helps learners find relevancy and meaning in a lesson and make connections between educational experiences and real life situations. It increases insight, and creates pathways to future learning.

Can singleton class be serialized?

Conclusion: Singleton class can also be serialized by keeping readResolve() method in the Singleton class. This may be a familiar solution but just in case for reference. So if we execute above code we will get following behaviour: “it has created two objects and one static reference for INSTANCE.

Is Java Reflection bad?

There are good points to Reflection. It is not all bad when used correctly; it allows us to leverage APIs within Android and also Java. This will allow developers to be even more creative with our apps. There are libraries and frameworks that use Reflection; a perfectly good example is JUnit.

Is reflection bad C#?

The main use of reflection is to inspect assemblies, types, and members of a class. The use of reflection is not recommended due to its bad performance because of all the security checks being done when calling a method or iterating through an object’s members.

What is the purpose of reflection in Java?

Reflection is a feature in the Java programming language. It allows an executing Java program to examine or “introspect” upon itself, and manipulate internal properties of the program. For example, it’s possible for a Java class to obtain the names of all its members and display them.

Where do we use reflection in C#?

You can use reflection to dynamically create an instance of a type, bind the type to an existing object, or get the type from an existing object and invoke its methods or access its fields and properties. If you are using attributes in your code, reflection enables you to access them.

How can we prevent immutable class from reflection?

There are several useful methods in the Collections class with respect to protecting immutable objects including unmodifiableCollection(), unmodifiableList(), unmodifiableMap() and unmodifiableSet() and more. We can use them in our immutable classes!

How can Singleton be prevented from reflection?

There are many ways to prevent Singleton pattern from Reflection API, but one of the best solutions is to throw a run-time exception in the constructor if the instance already exists. In this, we can not able to create a second instance.

How can Singleton be prevented from cloning?

You can avoid cloning by giving already created object by clone method. You need to override the clone() method only if your singleton class implements Cloneable interface or a class which implements Cloneable interface.

Should reflection be avoided?

Basically, avoid reflection in general code if at all possible; look for an improved design. So, it depends. If you only need equals and hashcode rarely, it’s pragmatic, and probably o.k., to use a general purpose reflection calculation.

How can we avoid serialization in Singleton?

As you can see, hashCode of both instances is different, hence there are 2 objects of a singleton class. Thus, the class is no more singleton. Overcome serialization issue:- To overcome this issue, we have to implement method readResolve() method. Above both hashcodes are same hence no other instance is created.

How do you stop a reflection in Java?

Avoid using it, try to write a code without the Reflection. The worst you can do is if you introduce some generic mechanism with it – a custom validation framework or a flow engine where class and method names are stored as a String (in a text file or a XML file).

How reflection can break Singleton?

As it is not possible to call enum constructor from the program, it is not possible for us to access them by Reflection also. Hence, reflection can’t break singleton property in case of enums. Enum Singleton cannot be broken using Serialization and Enums are also by default thread-safe.