Ques:- What is the full form of jstl?
Right Answer:
The full form of JSTL is JavaServer Pages Standard Tag Library.
The full form of JSTL is JavaServer Pages Standard Tag Library.
Ques:- In spring MVC, the annotation is not mentioned at DAO class then which exception is occurred?
Asked In :-
Bhanguz, gislen software,
Right Answer:
If the DAO class is not annotated with `@Repository`, a `BeanCreationException` may occur when Spring tries to create the bean, as it won't be recognized as a Spring-managed component.
If the DAO class is not annotated with `@Repository`, a `BeanCreationException` may occur when Spring tries to create the bean, as it won't be recognized as a Spring-managed component.
Ques:- Can you write any program
Right Answer:
```java
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
```
```java
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
```
Ques:- What is abstraction?
Asked In :-
Lucid Imaging, Damco Solutions, Orcapod Consulting Services, ABN AMRO, FANUC, Testrig Technologies, Algorithmic Trading Strategies Pty, IDS Infotech, Amagi Media, AMI Tech India,
Right Answer:
Abstraction is a programming concept that hides complex implementation details and shows only the essential features of an object. It allows developers to focus on what an object does instead of how it does it.
Abstraction is a programming concept that hides complex implementation details and shows only the essential features of an object. It allows developers to focus on what an object does instead of how it does it.
Ques:- Tell me about Abstraction?
Right Answer:
Abstraction is a fundamental concept in object-oriented programming that involves hiding the complex implementation details of a system and exposing only the necessary features or functionalities to the user. In Java, abstraction can be achieved using abstract classes and interfaces, allowing developers to define methods without providing their implementation, which can be completed by subclasses.
Abstraction is a fundamental concept in object-oriented programming that involves hiding the complex implementation details of a system and exposing only the necessary features or functionalities to the user. In Java, abstraction can be achieved using abstract classes and interfaces, allowing developers to define methods without providing their implementation, which can be completed by subclasses.
Ques:- What is Runtime Exceptions?
Right Answer:
Runtime exceptions are a type of exception in Java that occur during the execution of a program, indicating problems that are typically caused by bugs in the code, such as logic errors or improper use of APIs. They are subclasses of `java.lang.RuntimeException` and do not need to be declared in a method's `throws` clause. Examples include `NullPointerException`, `ArrayIndexOutOfBoundsException`, and `ArithmeticException`.
Runtime exceptions are a type of exception in Java that occur during the execution of a program, indicating problems that are typically caused by bugs in the code, such as logic errors or improper use of APIs. They are subclasses of `java.lang.RuntimeException` and do not need to be declared in a method's `throws` clause. Examples include `NullPointerException`, `ArrayIndexOutOfBoundsException`, and `ArithmeticException`.
Ques:- Tell me the things should be kept in mind while creating your own exceptions in Java?
Asked In :-
SRF, Signiwis Technologies, Kratin Mobile Software Solution, Majorel, western digital, dhandhania infotech,
Right Answer:
When creating your own exceptions in Java, keep the following in mind:
1. **Inherit from Exception**: Extend the Exception class for checked exceptions or RuntimeException for unchecked exceptions.
2. **Provide Constructors**: Include constructors that accept a message, a cause, or both.
3. **Use Meaningful Names**: Name your exception clearly to indicate the error it represents.
4. **Document the Exception**: Use Javadoc to explain when and why the exception might be thrown.
5. **Maintain Consistency**: Follow standard naming conventions and practices for exceptions.
6. **Avoid Overuse**: Only create custom exceptions when necessary; use existing exceptions when applicable.
When creating your own exceptions in Java, keep the following in mind:
1. **Inherit from Exception**: Extend the Exception class for checked exceptions or RuntimeException for unchecked exceptions.
2. **Provide Constructors**: Include constructors that accept a message, a cause, or both.
3. **Use Meaningful Names**: Name your exception clearly to indicate the error it represents.
4. **Document the Exception**: Use Javadoc to explain when and why the exception might be thrown.
5. **Maintain Consistency**: Follow standard naming conventions and practices for exceptions.
6. **Avoid Overuse**: Only create custom exceptions when necessary; use existing exceptions when applicable.
Ques:- When do you think Abstract methods are used?
Right Answer:
Abstract methods are used when you want to define a method in an abstract class that must be implemented by subclasses, ensuring that all subclasses provide their own specific implementation of that method.
Abstract methods are used when you want to define a method in an abstract class that must be implemented by subclasses, ensuring that all subclasses provide their own specific implementation of that method.
Ques:- Define Polymorphism?
Asked In :-
Elsner Technologies, Medha Servo Drives, Ultramain Systems, Orion Innovation, western digital,
Right Answer:
Polymorphism is a feature in Java that allows methods to perform different tasks based on the object that it is acting upon, enabling one interface to be used for a general class of actions. It can be achieved through method overriding (runtime polymorphism) and method overloading (compile-time polymorphism).
Polymorphism is a feature in Java that allows methods to perform different tasks based on the object that it is acting upon, enabling one interface to be used for a general class of actions. It can be achieved through method overriding (runtime polymorphism) and method overloading (compile-time polymorphism).
Ques:- Tell the two subclasses under Exception class?
Asked In :-
Ultramain Systems, Versant Online Solutions, Doyen Infosolutions Ltd, Orion Innovation, nielsen,
Right Answer:
Two subclasses under the Exception class are IOException and SQLException.
Two subclasses under the Exception class are IOException and SQLException.
Ques:- When do you think super keyword is used?
Right Answer:
The `super` keyword is used in Java to refer to the immediate parent class's methods or constructors. It is commonly used to access parent class members that are hidden by the child class or to call the parent class constructor.
The `super` keyword is used in Java to refer to the immediate parent class's methods or constructors. It is commonly used to access parent class members that are hidden by the child class or to call the parent class constructor.
Ques:- When do you think throws keyword is used?
Asked In :-
Hiya, dhandhania infotech, blue yonder gmbh, bnt soft, steepgraph systems pvt. ltd., proxima,
Right Answer:
The `throws` keyword is used in a method declaration to indicate that the method can throw one or more exceptions, allowing the caller of the method to handle those exceptions.
The `throws` keyword is used in a method declaration to indicate that the method can throw one or more exceptions, allowing the caller of the method to handle those exceptions.
Ques:- Define Abstract class?
Asked In :-
FANUC,
Right Answer:
An abstract class in Java is a class that cannot be instantiated on its own and may contain abstract methods (methods without a body) as well as concrete methods (methods with a body). It is used to provide a base for subclasses to implement the abstract methods.
An abstract class in Java is a class that cannot be instantiated on its own and may contain abstract methods (methods without a body) as well as concrete methods (methods with a body). It is used to provide a base for subclasses to implement the abstract methods.
Ques:- Can constructor be inherited?
Right Answer:
No, constructors cannot be inherited in Java.
No, constructors cannot be inherited in Java.
Ques:- What do you mean by the immediate superclass of Menu?
Asked In :-
Chella Software, blue yonder gmbh,
Right Answer:
The immediate superclass of the `Menu` class in Java is `MenuItem`.
The immediate superclass of the `Menu` class in Java is `MenuItem`.
Ques:- Does Java allow Default Arguments?
Right Answer:
No, Java does not allow default arguments.
No, Java does not allow default arguments.
Ques:- What do you mean by a Values Collection View ?
Right Answer:
A Values Collection View in Java refers to a view of the values contained in a map, allowing you to access and manipulate the values without directly interacting with the keys. It is obtained by calling the `values()` method on a map, which returns a collection of the map's values.
A Values Collection View in Java refers to a view of the values contained in a map, allowing you to access and manipulate the values without directly interacting with the keys. It is obtained by calling the `values()` method on a map, which returns a collection of the map's values.
Ques:- Describe type casting?
Asked In :-
Mind Infotech, springml, inc.,
Right Answer:
Type casting is the process of converting a variable from one data type to another. In Java, it can be done explicitly (using casting operators) or implicitly (automatically by the compiler) when converting compatible types. For example, converting an `int` to a `double` is an implicit cast, while converting a `double` to an `int` requires explicit casting.
Type casting is the process of converting a variable from one data type to another. In Java, it can be done explicitly (using casting operators) or implicitly (automatically by the compiler) when converting compatible types. For example, converting an `int` to a `double` is an implicit cast, while converting a `double` to an `int` requires explicit casting.
Ques:- Define Dynamic Binding(late binding)?
Right Answer:
Dynamic binding, also known as late binding, refers to the process of resolving method calls at runtime rather than at compile time. In Java, this occurs when a method is called on an object, and the specific method that gets executed is determined by the actual object's type, not the reference type. This allows for more flexible and dynamic code, particularly in the context of polymorphism.
Dynamic binding, also known as late binding, refers to the process of resolving method calls at runtime rather than at compile time. In Java, this occurs when a method is called on an object, and the specific method that gets executed is determined by the actual object's type, not the reference type. This allows for more flexible and dynamic code, particularly in the context of polymorphism.
Ques:- Tell the advantages of ArrayList over arrays?
Right Answer:
1. Dynamic size: ArrayList can grow and shrink in size, while arrays have a fixed size.
2. Easy to use: ArrayList provides built-in methods for adding, removing, and searching elements.
3. Type safety: ArrayList can hold objects of any type, and with generics, it can ensure type safety.
4. Better performance for frequent insertions and deletions: ArrayList can handle these operations more efficiently than arrays.
5. Supports iteration: ArrayList provides an iterator for easy traversal of elements.
1. Dynamic size: ArrayList can grow and shrink in size, while arrays have a fixed size.
2. Easy to use: ArrayList provides built-in methods for adding, removing, and searching elements.
3. Type safety: ArrayList can hold objects of any type, and with generics, it can ensure type safety.
4. Better performance for frequent insertions and deletions: ArrayList can handle these operations more efficiently than arrays.
5. Supports iteration: ArrayList provides an iterator for easy traversal of elements.
A Java Developer is a skilled software professional who specializes in the Java programming language, one of the most popular and enduring languages in the world. They are responsible for a wide range of tasks, from building complex enterprise applications to creating mobile apps and web services. The versatility of Java, coupled with its “write once, run anywhere” philosophy, makes it a preferred choice for a multitude of projects, and a Java Developer’s role is to leverage this power to create high-quality, efficient, and reliable software.
The day-to-day responsibilities of a Java Developer are diverse and often depend on their seniority and the type of project they are working on. They are typically involved in the entire software development lifecycle, which includes:
- Design and Development: A developer writes clean, well-documented, and efficient code that adheres to industry standards and best practices. They often work with frameworks like Spring, Hibernate, or Java EE to build the application’s backend logic.
- Collaboration: Java Developers work closely with other team members, including product managers, UI/UX designers, and quality assurance testers, to understand requirements and ensure the final product meets the needs of the business and its users.
- Testing and Debugging: They are responsible for writing unit tests to ensure the code works as expected and for debugging issues that arise during development or after deployment. This involves using tools to analyze code and identify and fix errors.
- Maintenance and Support: A developer’s work doesn’t end after the application is launched. They are often responsible for maintaining existing software, adding new features, and providing technical support to resolve issues and improve performance.
- Database Management: Many Java applications interact with databases, so developers need to have a strong understanding of database technologies like SQL and ORM (Object-Relational Mapping) tools.
A Java Developer must be proficient in not only the language itself but also its rich ecosystem of tools, libraries, and frameworks. They must also have a strong grasp of object-oriented principles, data structures, and algorithms. The role requires a strong problem-solving ability, meticulous attention to detail, and a commitment to continuous learning to keep up with the fast-paced evolution of technology. In essence, a Java Developer is a key architect and builder in the digital world, creating the software that powers much of our modern technology.
