If available, the same object reference is shared with the variable, else a new object is created. I am providing 50+ Java programming questions to test your coding skills. It’s good for beginners as well as experienced Java developers. The best part is that some of the questions are from the latest releases . If you can write Java programs using the latest features, it means you keep yourself up to date, which will work in your favor.
Find the detailed answer to How HashMap works internally in Java here. Dynamic method dispatch is also known as Run time polymorphism. It is a mechanism by which a call to an overridden method is resolved at run time. At runtime, it is the type of object being referred to not the type reference of the variable that decides which version of an overridden method needs to be executed. The static method belongs to the class level, not the object level. In method overriding, it is the object that decides which method is to be called. Here’s a list of our top 93 Java interview questions that will walk you through the process of a Java developer interview – step by step.
Q34. What is an infinite loop in Java? Explain with an example.
If you have an interview coming up, then I highly suggest you double down on concurrency and this is an excellent course to prepare for Multithreading and Concurrency Interview questions in Java. Nevertheless, here is the list of topics I suggest to any Java developer who is serious about interviews. For Java, web application developers, JSP, Servlet, Spring, and Hibernate are more critical than multi-threading and JVM internals. Similarly, for an Android developer, apart from knowledge of Java fundamentals, knowing Android API is more important. The interview will then simultaneously move onto more difficult questions, many of which we list below. Which of them makes sense for you differs depending on several things. A developer usually lists the versions they’ve used most recently on their CV.
Candidates should list attention to detail and excellent problem-solving skills as key attributes in a Java developer. It’s a good idea to have multiple certifications – this allows the hiring manager to perceive you as an all-rounder and can improve the chances of your employability. Do be mindful that this won’t guarantee you the job it if the desired attributes for that particular role are missing though. Here are top five questions you will face if you are a developer within the tech space. Full Scale helps businesses grow quickly by providing access to highly skilled, remote developers.
How to Compile and Run a Java Class from Command Line?
Various methods like execute(), executeUpdate(), executeQuery, etc. are provided by JDBC to interact with the database. Statement execute is used to execute any SQL query and it returns TRUE if the result is an ResultSet such as running Select queries. The output is FALSE when there is no ResultSet object such as running Insert or Update queries. We can use getResultSet() to get the ResultSet and getUpdateCount() method to retrieve the update count. The DatabaseMetaData interface returns the information of the database such as username, driver name, driver version, number of tables, number of views etc. It provides factory method that returns the instance of Connection. A Marker interface can be defined as the interface having no data member and member functions.
- This question tests the technical expertise of a Java developer.
- In contrast, volatile allows concurrent executions from multiple threads by forcing them to read the variable from main memory directly instead of CPU cache.
- One of the benefits of this method is that it assists in defining a specific class type behavior so that a subclass can use a parent class method based on its type.
- On the other hand, candidates need to also repeat the basic information prior to the interview in order to fully showcase their potential.
- A Java server page can contain fragments of Java program, which execute and instantiate Java classes.
It is used to do both creation and initialization in a single statement. When these both are used together, it is known as Double Brace Initialization. The inner class has a reference to the enclosing outer class, generally using the ‘this’ pointer. When you create a subclass instance, you’re how to become a java developer also creating an instance of the parent class, which is referenced to by the super reference variable. An empty interface i.e interface without methods and fields is called a marker interface in java. Java.io.Serializable and java.lang.Cloneable are some of the examples of marker interface.
What Drew You to a Career in Java Development?
Batch processing helps you to group related SQL statements into a batch and execute them instead of executing a single query. By using batch processing technique in JDBC, you can execute multiple queries which makes the performance faster.
The form of the data being stored, the way it is collected and how often it is accessed all have to do with the type of database to use. For instance, chat apps may need to store chat histories, user profiles, images or videos — these different formats can all affect the type of database that works best.