What does the keyword “synchronize” mean in java. When do you use it?
Synchronize is used when u want to make ur methods thread safe. The disadvantage of synchronise is it will end up in slowing down the program. Also if not handled... Read more »
‘Java Interview Questions’ - KyaPoocha.com
What are native methods? How do you use them?
Native methods are methods that are defined as public static methods within a java class, but whose implementation is provided in another programming language such... Read more »
What is JDBC? Describe the steps needed to execute a SQL query using JDBC.
The JDBC is a pure Java API used to execute SQL statements. It provides a set of classes and interfaces that can be used by developers to write database applications. The... Read more »
What does the “abstract” keyword mean in front of a method? A class?
Abstract keyword declares either a method or a class. If a method has a abstract keyword in front of it,it is called abstract method.Abstract method has no body.It... Read more »
What is the difference between instanceof and isInstance?
instanceof is used to check to see if an object can be cast into a specified type without throwing a cast classexception. isInstance() Determines if the specified... Read more »
What is the difference between a public and a non-public class?
A public class may be accessed outside of its package. A non-public class may not be accessed outside of its package. Read more »
What is a layout manager?
A layout manager is an object that is used to organize components in a container. Read more »
What is the difference between set and list?
Set stores elements in an unordered way but does not contain duplicate elements, whereas list stores elements in an ordered way but may contain duplicate elements. Read more »
What is runnable?
Its an Interface through which Java implements Threads.The class can extend from any class but if it implements Runnable,Threads can be used in that particular application. Read more »
What is preemptive and Non-preemptive Time Scheduling?
Preemptive: Running tasks are given small portions of time to execute by using time-slicing. Non-Preemptive: One task doesn’t give another task a chance to run... Read more »
What are Transient and Volatile Modifiers?
Transient: The transient modifier applies to variables only and it is not stored as part of its object’s Persistent state. Transient variables are not serialized. Volatile:... Read more »
Describe java’s security model.
Java’s security model is one of the most interesting and unique aspects of the language. For the most part it’s broken into two pieces: the user adjustable security... Read more »
What methods can be overridden in Java?
In C++ terminology, all public methods in Java are virtual. Therefore, all Java methods can be overwritten in subclasses except those that are declared final, static,... Read more »
What is constructor chaining and how is it achieved in Java ?
A child object constructor always first needs to construct its parent (which in turn calls its parent constructor.). In Java it is done via an implicit call to the... Read more »
How many static init can you have ?
As many as you want, but the static initializers and class variable initializers are executed in textual order and may not refer to class variables declared in the... Read more »
Describe the Garbage Collection process in Java ?
The JVM spec mandates automatic garbage collection outside of the programmers control. The System.gc() or Runtime.gc() is merely a suggestion to the JVM to run the... Read more »
What is an Iterator interface?
The Iterator interface is used to step through the elements of a Collection. Read more »
Explain the life cycle methods of a Servlet.
The javax.servlet.Servlet interface defines the three methods known as life-cycle method. public void init(ServletConfig config) throws ServletException public void... Read more »
What is the difference between the getRequestDispatcher(String path) method of javax.servlet.ServletRequest interface and javax.servlet.ServletContext interface?
The getRequestDispatcher(String path) method of javax.servlet.ServletRequest interface accepts parameter the path to the resource to be included or forwarded to,... Read more »
Explain ServletContext.
ServletContext interface is a window for a servlet to view it’s environment. A servlet can use this interface to get information such as initialization parameters... Read more »