130+ Core Java Interview Questions and Answers in 2023

Java developers possess expert knowledge of one of the most diverse programming languages available. It can be used for many applications, from creating and building web-based applications to designing sophisticated desktop applications. 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. As we know that the static context belongs to the class, not the object.

The FailFast iterators tend to fail and throw an exception called ConcurrentModificationException. Java Cryptography Architecture gives a platform and provides architecture and application programming interfaces that enable decryption and encryption. The Externalizable interface helps with control over the process of serialization. An “externalisable” interface incorporates readExternal and writeExternal methods. JVM has a Just in Time compiler tool that converts all the Java source code into the low-level compatible machine language. Therefore, it runs faster than the regular application. Write a java program to check if any number given as input is the sum of 2 prime numbers.

Senior Java Developer Interview Questions

The new operator returns a reference to an object after dynamically allocating memory for it. Yes, even with a garbage collector in place, the programme could still run out of memory. Garbage collection aids in identifying https://remotemode.net/ and removing programme objects that are no longer needed in order to release the resources they use. When an object in a programme cannot be reached, trash collection is executed with respect to that object.

• In this case, baseMethod is present in Base class; therefore, it is compiled successfully.
• The GET method in HTTP should be used only to retrieve resources from a web server, without altering the state of the application in any way.
• ThreadStates is the enum with fixed constants fields START, RUNNING, WAITING, and DEAD.
• In particular, you have to do a bit of research about the company.
• Typically, performance issues are reported by testers or users sometime after a feature has been shipped to production.
• I think more convincing reason for not supporting multiple inheritance is complexity involved in constructor chaining, casting etc rather than diamond.

As a result, when an element is inserted into the middle of the list, the elements that follow must all be shifted accordingly. Vector is synchronized, so if a thread-safe implementation is not needed, it is recommended to use ArrayList rather than Vector. So, garbage collection helps in reducing the chances of a program going out of memory but it doesn’t ensure that. When a method is declared as final, it can NOT be overridden by the subclasses.

What is the Daemon Thread?

To help you ace your Java interview, this article will provide you with the most frequently asked Java interview questions for 5 years of experience in FAANG interviews. Yes, we can have any number of main methods in a Java program by using method overloading. Method overriding cannot be achieved without inheritance. By method overriding, we can give a specific implementation of some basic method contained by the base class.

It provides factory methods that returns the instance of Statement, PreparedStatement, CallableStatement and DatabaseMetaData. The constructor become a java developer chaining follows the process of inheritance. The constructor of the sub class first calls the constructor of the super class.