AlgoSec Java Developer Interview Questions and Answers

I have used the Singleton design pattern in my Java projects.

• Singleton pattern ensures that only one instance of a class is created and provides a global point of access to it.

• It is useful when we want to limit the number of instances of a class to one.

• Example: Creating a Logger class as a Singleton to ensure only one instance is used throughout the application.

Difference between @Controller and @RestController in Java.

• Both are used for creating RESTful web services in Java.

• @Controller returns the view while @RestController returns the data in JSON or XML format.

• @RestController is a combination of @Controller and @ResponseBody annotations.

• Use @Controller for traditional web applications and @RestController for RESTful web services.

Java 11 has more features and improvements than Java 8.

• Java 11 has introduced new features like var keyword, HTTP client API, and local variable syntax for lambda parameters.

• Java 11 has removed some features like JavaFX and Nashorn JavaScript engine.

• Java 11 has improved performance and security.

• Java 8 is no longer supported for commercial use.

• Java 11 requires a higher version of the operating system than Java 8.

Array is a fixed-size data structure while ArrayList is a dynamic-size data structure.

• Array is a primitive data type while ArrayList is a class in Java.

• Array can hold only homogeneous data types while ArrayList can hold heterogeneous data types.

• Array uses [] to declare while ArrayList uses <>.

• Array can be multidimensional while ArrayList is always one-dimensional.

• Array length is fixed while ArrayList size is dynamic an