Difference Between Interface vs. Abstract Class in Java

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Main Difference

The difference between interface and abstract class in java is that interface in java can never be instantiated as the method are unable to perform any action on invoking whereas abstract class in java can n be instantiated as the method can perform any action on invoking.

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Interface vs. Abstract Class in Java

Java is an object-oriented programming language that uses both compiler and interpreter. Mostly all software’s are made in Java programming language. Java code can be written on Windows, Linux, and Mac OS. The syntax of C and C++ programming language is quite the same. Java produces browser to run programs that help in making a graphical user interface. Java programming language is in used and trend these days. To write Java code, a programmer needs software development kit (SDK) that includes a compiler, interpreter that is not required in C++. Java is an object-oriented programming language that uses both compiler and interpreter. Mostly all software’s are made in Java programming language. Java code can be written on Windows, Linux, and Mac OS. The syntax of C and C++ programming language is quite the same. The interface in java can never be instantiated as the method are unable to perform any action on invoking whereas abstract class in java can n be instantiated as the method are able to perform any action on invoking. An interface in java contains methods and fields. In the interface the method is declared are abstract. They methods are always public, static and final. At the time of declaration, the fields must be initialized. In runnable interface, in java, multiple threads share the same objects. Like thread class runnable is also an interface in java.lang package. To define a thread, a runnable interface is created. The thread is program execution that uses the process resources for the task. The class is one of the most important features in Java programming. We cannot implement a java implement in java programming if we don’t know about to implement the class. Classes in java programming are also used to create objects because class creates reference type. In the signature of a class, there is a body of class that is the class’s name and all the information. In the main body of the class, there is fields and methods of the class. If a class has more than one abstract method it is known as abstract class. Keyword abstract is used to create an abstract class. Other classes can inherit from the abstract class. The process contains thread; the process is a container and thread is a content of that container. The kernel of operating system allocates a stack and a thread control block to each thread. The thread control block is responsible for switching between the threads of the same process. There are types of threads such as kernel-lever threads, user-level threads, hybrid threads. There are further three states of thread such as running, ready and blocked. There is priority property in threads in this way there are multiple threads are active. One system can create one thread. The thread can share data and information whereas process cannot. In multithreading, multiple threads are created. A thread in multithreading is a process means a code segment of a process. A thread in the runnable interface has its own thread ID, program counter, registers, and stack. If we create separate processes for each service, then each processor share code, data and system resources. If we do not create threads, the system can get exhausted. Creating threads can make processor easy for working. The responsiveness is increased in multithreading, and this is the best advantage of using multithreading. The big advantage of the runnable interface in java is resource sharing and in resource sharing the several threads of a process share same code.

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Comparison Chart

BasisInterfaceAbstract class
MeaningThe interface in java can never be instantiated as the method are unable to perform any action on invokingAbstract class in java can n be instantiated as the method are able to perform any action on invoking.
Concrete methodsThe interface in java does not have concrete methodsAbstract class in java have concreated methods
MethodsIn interface, methods should be public or abstractIn abstract class, it is not important to have public or abstract method.
InitializationIn interface variable initialization should be at the time of declarationIn abstract class initialization can be at any time.

What is Interface in Java?

A class can only inherit a single class; interface was created to solve this problem. Using interface class can inherit more than one class. The structure of the interface is very similar to a class. The keyword that is used to implement the interface in java is an interface. In the interface, a method is not defined inside the body of the interface. The class must be defined inside the body of the interface. The method of the class must always be public. An interface in java contains methods and fields. In the interface the method is declared are abstract. They methods are always public, static and final. At the time of declaration, the fields must be initialized. In runnable interface, in java, multiple threads share the same objects. Like thread class runnable is also an interface in java.lang package. To define a thread, a runnable interface is created. The thread is program execution that uses the process resources for the task. The process contains thread; the process is a container and thread is a content of that container. The kernel of operating system allocates a stack and a thread control block to each thread. The thread control block is responsible for switching between the threads of the same process. There are types of threads such as kernel-lever threads, user-level threads, hybrid threads. There are further three states of thread such as running, ready and blocked. There is priority property in threads in this way there are multiple threads are active. One system can create one thread. The thread can share data and information whereas process cannot. In multithreading, multiple threads are created. A thread in multithreading is a process means a code segment of a process. A thread in the runnable interface has its own thread ID, program counter, registers, and stack. If we create separate processes for each service, then each processor share code, data and system resources. If we do not create threads, the system can get exhausted. Creating threads can make processor easy for working. The responsiveness is increased in multithreading, and this is the best advantage of using multithreading. The big advantage of the runnable interface in java is resource sharing and in resource sharing the several threads of a process share same code.

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What is Abstract class?

If a class has more than one abstract method, it is known as abstract class. Keyword abstract is used to create an abstract class. Other classes can inherit from the abstract class. The class is one of the most important features in Java programming. We cannot implement a java implement in java programming if we don’t know about to implement the class. Classes in java programming are also used to create objects because class creates reference type. In the signature of a class, there is a body of class that is the class’s name and all the information. In the main body of the class, there is fields and methods of the class. The objects in class can be static and non-static. The keyword class is used for making a class in java programming. Each object created in java contain and copy field and methods. Access specifier decides the visibility and accessibility of the members of the subclass. Inheritance can be done by using access specifier in Java programming. One class inherit the objects and methods of the other class.

Key Differences

  1. The interface in java can never be instantiated as the method are unable to perform any action on invoking whereas Abstract class in java can n be instantiated as the method are able to perform any action on invoking.
  2. The interface in java does not have concrete methods whereas Abstract class in java have concreated
  3. In the interface, methods should be public or abstract whereas in abstract class it is not important to have public or abstract method.
  4. In the interface, variable initialization should be at the time of declaration whereas in abstract class initialization can be at any time.

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