eClinicalWorks Software Engineer and Fullstack Developer Interview Questions, Process, and Tips

Immutable class is a class whose instances cannot be modified after creation.

• Instances of immutable class cannot be changed once created

• Immutable classes are often used for objects that should not be modified, like dates or strings

• Examples of immutable classes in Java are String, Integer, and LocalDate

Immutable class can be created by making all fields private and final, providing only getters and no setters.

• Make all fields private and final

• Provide only getters, no setters

• Avoid modifying state within the class

A singleton class is a class that can only have one instance created throughout the entire application.

• Singleton classes are often used for logging, driver objects, caching, thread pools, database connections, etc.

• They have a private constructor to prevent instantiation from other classes.

• They provide a global point of access to the instance.

Immutable class is a class whose state cannot be modified after creation.

• Use final keyword to make class immutable

• Make all fields private and final

• Do not provide setter methods

• Return new instances when modifying state

Immutable class program in Java

• Use the 'final' keyword to make class immutable

• Make all fields private and final

• Do not provide setter methods, only getter methods

• Ensure deep copy of mutable objects in constructor or getter methods

Controller is a general term for classes that handle incoming requests, while RestController is specifically for RESTful web services in Spring.

• Controller is a general term for classes that handle incoming requests in a web application.

• RestController is a specialized version of a controller that is used for creating RESTful web services in Spring framework.

• RestController is annotated with @RestController, which combine...read more

No, controller and service annotations serve different purposes in a software application.

• Controller annotations are used to define the entry points for incoming requests and map them to specific methods in a controller class.

• Service annotations are used to mark a class as a service component that can be injected into other classes for business logic implementation.

• Mixing up controller and service annotations can lead ...read more

=== is a strict equality operator in JavaScript that checks if two values are equal in type and value.

• === compares two values without type conversion

• Returns true if both values are strictly equal, false otherwise

• Example: 5 === '5' returns false because they are of different types

Heap memory is used for dynamic memory allocation, while stack memory is used for static memory allocation.

• Heap memory is allocated at runtime and can be accessed randomly, while stack memory is allocated at compile time and is accessed in a LIFO order.

• Heap memory is managed manually by the programmer, while stack memory is managed automatically by the system.

• Heap memory is larger in size compared to stack memory, but ...read more

JSP stands for JavaServer Pages, a technology used for creating dynamic web pages using Java.

• JSP allows embedding Java code in HTML pages

• It is compiled into servlets by the server before execution

• JSP simplifies the process of developing web applications by separating the presentation layer from the business logic