Top 25+ Java Developer Interview Questions

If the target is larger, it recursively calls itself with the right half of the range. The process continues until the element is found or the low index becomes greater than the high index. The user of this program must first enter the matrix’s row and column counts before entering the matrix’s components.

java developer interview questions

By asking this question, the candidate has the chance to demonstrate their working knowledge when it comes to Agile principles and Scrum mentality. Furthermore, the candidate can explain what their role in the team is. Java is known for its object-oriented programming structure. Real-world items or subjects turn into code as objects, and these objects communicate with other objects.

Most Asked Key Account Manager Interview Questions (With Answers)

Consider the following example which illustrates how can we use this keyword to achieve constructor chaining. No, this cannot be assigned to any value because it always points to the current class object and this is the final reference in Java. However, if we try to do so, the compiler error will be shown. Yes, we can declare static variables and methods in an abstract method.

java developer interview questions

Explain your answer, including any other alternatives you may be aware of. The exception IOException is already caught by the alternative Exception. The given print statement will throw a java.lang.NullPointerException because the OR logical operator evaluates both the literals before returning the result.

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Constructor chaining in Java involves calling a constructor from another in connection with the current object. To make this happen, a subclass constructor has to be able to invoke its constructor first. Garbage collection is used when an object is either not being referenced or isn’t being used. At that point, garbage collection can automatically destroy the object. Inheritance is a core principle in object-oriented programming. It allows an object to inherit the properties of a different class.

In comparison to input/output streams, the Reader/Writer classes are more efficient, handle all Unicode characters, and are useful for internalization. Use Reader/Writer classes java 7 certifications instead of binary data, such as pictures, unless you do so. Here are 10 essential interview questions and sample answers to help identify the best candidates for this role.

What is a daemon thread?

The main benefit is of providing a way to control and manage the state and the behavior of an object and also protecting it from modification and unauthorized access at the same time. This method can access both static and non-static methods of the class. The instance method can be called on a specific instance of a class using the object reference. An Array in Java is a data structure that is used to store a fixed-size sequence of elements of the same type.

In other words, we can say that the final variable once assigned to a value, can never be changed after that. The final variable which is not assigned to any value can only be assigned through the class constructor. No, We cannot overload the methods by just applying the static keyword to them(number of parameters and types are the same). In Java, method overloading is not possible by changing the return type of the program due to avoid the ambiguity.

Object-oriented paradigm aims to incorporate the advantages of modularity and reusability. Objects are the instances of classes which interacts with one another to design applications and programs. There are the following features of the object-oriented paradigm. A Java developer should have a strong understanding of core Java concepts such as object-oriented programming, data types, control structures, and exception handling. Additionally, knowledge of frameworks like Spring, Hibernate, and web development technologies like Servlets and JSP is beneficial. Other than Technical Skills Problem-solving, debugging, and critical thinking skills are also highly valued.

  • This avoids ClassCastException at Runtime because you will get the error at compilation.
  • In this example, we are going to copy the values of one object into another using java constructor.
  • Additionally, it’s important to discuss how you test and monitor your applications for memory leaks.
  • As with any coding interview, you’ll want to study several algorithms and be prepared to implement them in Java.
  • You’ll want to tailor your preparation based on the level and responsibilities of the job you’re applying for, as well as the company.
  • The ResultSetMetaData interface returns the information of table such as total number of columns, column name, column type etc.

It is mostly used for reading binary data such as images, audio files, or serialized objects. All the stream classes can be divided into two types of classes that are ByteStream classes and CharacterStream Classes. The ByteStream classes are further divided into InputStream classes and OutputStream classes. CharacterStream classes are also divided into Reader classes and Writer classes.


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