10 Senior Java Developer Interview Questions

Static binding is used during overloading, whereas dynamic binding is used during methods overriding. Yes, the main method can be overloaded as many times as we want. Nevertheless, JVM prefers to call the main method with the help of its predefined calling method. For every object, the Garbage Collector calls the finalize() method just for one time.

java developer interview questions

When an object in a programme cannot be reached, trash collection is executed with respect to that object. If there is not enough memory available to create new objects, a garbage collector is used to free up memory for things that have been removed from the scope. When the amount of memory released is insufficient for the creation of new objects, the program’s memory limit is exceeded. In the event that an exception is not caught, it is initially thrown from the top of the stack and then moves down the call stack to the preceding method. The runtime system looks for a way to handle an exception that a method throws.

What is the difference between an object-oriented programming language and object-based programming language?

There are only a few situations in which the finally block does not execute, such as VM crash, power failure, software crash, etc. If you don’t want to execute the finally block, you need to call the System.exit() method explicitly in the finally block. Hibernate provides a reference implementation of Java Persistence API, that makes it a great choice as ORM tool with benefits of loose coupling. We can use the Hibernate persistence API for CRUD operations.

We can simulate the inheritance of classes with the real-time objects which makes OOPs more realistic. Therefore, this cannot be assigned to any new value whereas the current class object might not be final and can be changed. As we know, that this refers to the current class object, therefore, it must be similar to the current class object. However, there can be two main advantages of passing this into a method instead of the current class object.

Core Java Interview Questions | Set 1

ResultSet returned is never null even if there are no records matching the query. 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.

  • We can use getResultSet() to get the ResultSet and getUpdateCount() method to retrieve the update count.
  • However, we can copy the values from one object to another like copy constructor in C++.
  • Model-View-Controller frameworks call controller methods based on routing rules.
  • The Java Classloader is the part of the Java runtime environment that loads classes on demand into the JVM .
  • Relax, the expectation from the 2 to 4 years experienced guy is not the same as for senior java developers.

While an ArrayList does not contain primitive data types. Instead of the actual object, an ArrayList includes the references to the objects‘ many locations in how to become a java developer memory. The objects are not kept in consecutive memory regions because of this. The this keyword is a reference variable that refers to the current object.

Creating an Online Quiz Application Using JSP Servlet

The short datatype can be promoted to int, long, float or double. The char datatype can be promoted to int, long, float or double and so on.

  • But there is the condition that super() must be the first statement in the block.
  • On Heap memory, garbage collection is employed to release the memory used by objects with no references.
  • This() can be used to invoke the current class constructor.
  • Your interviewer will want to know if you have the technical skills to do the job, but they will also be looking for evidence that you’re a good fit for the company culture.
  • On the other hand, sleep () is using for polling or to check determined results.
  • However, there is only one parameterized constructor in the class Test.
  • OutOfMemoryError is the subclass of java.lang.Error which generally occurs when our JVM runs out of memory.

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